I noticed lately that a lot of threads were getting made from people joining the fellowship of PC gamers for the first time, or are returning to the flock after years of absence, and found themselves lost and overwhelmed by their choices and wondering where exactly they should start with PC gaming. Unlike the consoles, PC gaming has over 20 years of great games for people to find and enjoy for relatively cheap if you know to look in the right places. So it is understandably confusing to try and jump into it if you are unfamiliar with the platform.
 
So to help keep the forums from being cluttered with hundreds of "Tell me what PC games to buy!" threads, I figured someone could just make a master list like the ones already being used for the PS3 and Wii and that way we can link our lost brothers to it.
 
In my first round of this I will hope to get as much as I can, but I'm sure there will be other great games that I simply don't think of. So feel free to chime in with suggestions below and I will do my best to keep updating the list as we go along. 
  

Suggestion Guidelines

The point of this is not to list off the best PC games of all time, but to be used as a guide for people new to the PC platform to know where to start when looking for games to play on their new PCs.

Where to Buy

• Steam- This site has an RSS feed that you can subscribe to for updates of everything that goes on sale on steam.
  
• Good Old Games
  
• Games for Windows Live
• Impulse
• Direct to Drive
• Blizzard Store 
• Gamers Gate
  

Strategy

RPG

Adventure Games

Racing

Action

Shooter

Indie

Sports

Sim

MMO

Multi-platform Games That Are Better On PC

You should add Arx Fatalis to the RPG portion

Please change Fallout Brotherhood of Steel to Fallout Tactics: Brotherhood of Steel.  Otherwise it might get confused with the shit game that came out for xbox.  Fallout Tactics is fantastic and underappreciated.

Trackmania, of course.

" You should add Arx Fatalis to the RPG portion "

" Please change Fallout Brotherhood of Steel to Fallout Tactics: Brotherhood of Steel.  Otherwise it might get confused with the shit game that came out for xbox.  Fallout Tactics is fantastic and underappreciated. "

" Trackmania, of course. "

u have planescape torment, i believe u handled this list perfectly 
oh and system shock 2!!! 
 
add  anachronox super funny rpg, really unique but i dont know if its easy to find

So is this PC only games or just whatever is worth playing as long as it's on PC?
 
If that's the case I recommend Dirt 2 for the racing category. Still looks beautiful graphically and it's got sick drifting.

Awesome idea, cheers!
Also, how good does a game need to be to fit? I've only played DiRT 2 of the DiRT series but it reviewed well and I enjoy it. Got off steam.

Good idea. How about adding GamersGate to the store list?

" So is this PC only games or just whatever is worth playing as long as it's on PC?  If that's the case I recommend Dirt 2 for the racing category. Still looks beautiful graphically and it's got sick drifting. "

Great thread, should be stickied once a more comprehensive list is sorted out.  
 
Just to offer some initial suggestions from a quick glance: 
 
1) I don't think STALKER belongs in RPGs; should probably just be under "first person shooter" if such a category is made.  
2) GamersGate is actually one of the more prominent DD services and should be added. 
3) SteamGameSales offers up to date sale info on Steam and all of the aforementioned DD services alike; paired with an RSS reader it becomes a great tool.  
4) The Anno/Dawn of Discovery series should be added to Strategy 
5) Recettear: An Item Shop's Tale should be added under RPGs (or will you make a separate category for indies?)  
6) King's Bounty series could be added for RPGs
7) GRID, Dirt 2, Dirt 1 and FUEL are my suggestions for racing (basically all the Codemasters racing games). Proof: 
 
  

perhaps a FPS category with Crysis and STALKER and Deus Ex under it, and a TPS category with Max Payne and something else... ?

Where is crysis?

" @Geno: I'm not very familiar with the Stalker franchise so I will keep it with FPS unless I get a lot saying otherwise. I always thought it had a lot of RPG elements so that's why I put it there. If it's something that is equal parts of two different genres then I plan to put it in both just to keep both sides of any argument happy.

add: 
 anachronox (rpg)   
star treck elite force 
sin 
nolf (no one lives forever) 
dungeon keeper 1 & 2 
 
admittedly older games that might be hard to find but all are pc only games that range from great to excellent

Gears of War could be added for shooters as well.   

Sniper Ghost Warrior? I heard that game was kind of shit. 

Hey, if having a better version than consoles mutiplatformwise, then what about games like mass effect 2. What about 3rd person shooters? Is there a category for that too? I find most of the multiplatform games are superior on the pc.

I'd put Fallout Tactics in the strategy section since it's not at all similar in gameplay to the original Fallout games. Also make sure the entry STALKER says "series". Also add Arcanum to the RPG list. 
 
edit: Also it would be wise to split the Vampire the Masquerade entry into two different entries for two very different games ( VTM-Bloodlines and VTM-Redemption), or changed to mention just Bloodlines. I would say Bloodlines was worth playing while Redemption was not.
 
And mention that the link beside Steam (to steamgamesales) also has RSS feeds for multiple sites including Direct2Drive, EA Store, Impulse, and Gamer's Gate as well as regular old Steam.
 

@Laketown

" @crusader8463 said:

" @Geno: I'm not very familiar with the Stalker franchise so I will keep it with FPS unless I get a lot saying otherwise. I always thought it had a lot of RPG elements so that's why I put it there. If it's something that is equal parts of two different genres then I plan to put it in both just to keep both sides of any argument happy.

It is BARELY an RPG, in that you collect better versions of weapons. put it under FPS. "

Add LOTRO to MMOs.

  @Geno said:

" Gears of War could be added for shooters as well.   Sniper Ghost Warrior? I heard that game was kind of shit.  "

"

Hey, if having a better version than consoles mutiplatformwise, then what about games like mass effect 2. What about 3rd person shooters? Is there a category for that too? I find most of the multiplatform games are superior on the pc.

"

I am not exagerating and it's more than the mouse and keyboard setup crusader. The framerates are so much higher, so are the resolution, textures quality and anti aliasing. Imo it's like night and day from my experience, maybe you are using a less display or videocard. If you don't want to include multiplatform games, well, pc has less exclusives these days. Do what you want.

Indie:  Osmos, DEFCON, Darwinia, Uplink, World of Goo, Machinarium, Trine  (dont know if World of Goo is good on wii)
Shooter: Alien Swarm (Free on Steam)
Strategy: Galactic Civilizations II + Expansions (Impulse) , Sid Meier's Alpha Centauri,  Age of Empires, Rise of Nations
Sims: Falcon 4.0, IL-2 Sturmovik Series, Railroad Tycoon Series, X-Wing Series, Freespace 2

Good list. Might want to throw in a "+ expansion" for the Baldur's Gate titles too, since you did for Diablo II, and I haven't played BG1, but the expansion for BG2 (Throne of Bhaal) is fantastic. Not sure if this is the place for it, but there are older game or games with fan patches worth mentioning, like Vampire The Masquerade: Bloodlines  unofficial patch:   http://www.patches-scrolls.de/vampire_bloodlines.php  
 
also, widescreen and other fixes for all the infinity engine games (PS;T, BG1,2, etc):  http://www.gibberlings3.net/widescreen/ 
 
oh, also, you have TFC on there under shooters, probably want to put TF2 in there as well.

I feel like there should be an adventure game category for Sam & Max Series, Monkey Island Series, Grim Fandango, Full Throttle, Syberia, Myst, Longest Journey etc.

Braid, Shatter, Super Meat Boy, VVVVVV,  all indie all on steam.

Add Broken Sword 3 in adventure games. That game is great! 
 
You could also add a horror and point and click categories.  
 
The list a good idea, and it is very well done. Thanks for your effort!

o_o How did I miss this. Anyway, some thoughts:
 
1. This list is pointless without any description of WHY the games listed are worth getting or at least why they're different/unique/interesting/etc... If I were just going by this list, then as far as I could tell Starcraft is the same thing as Evil Genius. 
2. Indie is not a genre and not only that, it's a bad classification. People who enjoy RPGs might look in the RPG section and then completely miss Recettear because it's just lumped in the indie section. 
3. Listing all games in a series together isn't that helpful, as some games in a series are very different to others. An example is X-com, the 4th and 5th games aren't strategy games at all.
4. System Shock 2 is very notably not easily available for purchase.
5. Maybe I'll add some suggestions later...

This is a great list. Should be a sticky, I've bookmarked it! Thanks.

Batman: AA plays way better on PC and has awesome Physx support if you have an Nvidia card - only game to really show off what that can do well so far.

Really good list, but this is only the tip of the iceburg really out of the pc demographic of games. I still wish I could go back and play system shock 2. Call me stupid too, but I could never quite get dosbox to work or get other versions of windows properly installed to play it. If good old games had it i buy in a milisecond