Having seen a particularly cheap deal on ebay I ended up getting myself a mega drive. Having been very much a SNES kid in my youth I don't know what I should get for this classic console. So here I turn to you, the Giant Bomb user, what games should I get for my Mega Drive? I already own ; 
Mega Games 1 (Columns, Super Hang-On and World Cup Italia),  
Mega Games 2 (Golden Axe, The Revenge of Shinobi and Streets of Rage) 
Mega Games 3 (Alien Storm, Super Monaco GP and Super Thunder Blade) 
Road Rash 2 
Sonic the Hedgehog 
Sonic the Hedgehog 2 
 
I also have Desert Strike on it's way to me. So what games should I get?

Oh god, I was planning on starting a blog with this in mind. 
 
In fact, I do recall making a definitive Mega Drive list on this site before. 
 
Found it. 
  
Aladdin
Alien Soldier 
Alien Storm 
Batman (by Sunsoft) 
The Story of Thor 
Bonanza Brothers  
Caslte of Illusion 
World of Illusion (great co-op)  
Castlevania Bloodlines 
Columns 
Columns III 
Comix Zone 
Contra Hard Corp (probably the furtherest thing away from 'easy') 
Decap Attack  
Dragon: The Bruce Lee Story (a really unique fighter)
Dr Robotnik's Mean Bean Machine (aka Pyro Pop) 
Dynamite Headdy (my second favourite game of all time- I urge everyone to play this) 
Earthworm Jim 
Earthworm Jim 2 
Ecco The Dolphin 
Ecco- The Tides of Time (again- mindblowingly hard but worth playing) 
Fatal Labyrinth (really, really simple but I've hooked on it on the 360)  
Ghouls 'n Ghosts (another hard motherfucker) 
Golden Axe 
Golden Axe II 
Golden Axe III (both sequels are inferior to the original game- but still worth playing)Gunstar Heroes 
Kid Chameleon 
Lemmings (better than the SNES version) 
Lemmings 2: The Tribes 
Michael Jackson's Moonwalker (don't laugh- its actually a pretty damn good game if you bother to play it) 
Micky Mania 
Micro Machines '96 Championship Edition (the one with the track creator) 
Mortal Kombat (the Megadrive version specifically is my favourite game in the whole series)
Mortal Kombat II 
Ultimate Mortal Kombat Trilogy (no thats not a typo- look it up- its better than most 'real MK games) 
Outrun 
Pulseman 
Quackshot 
Revenge of Shinobi 
Ristar 
Road Rash 
Road Rash 2 
Road Rash 3: World Tour (go with the latter 2 games if you have the choice)
Rocket Knight Adventures 
Shadow Dancer (Shinobi spin-off) 
Shinobi III- Revenge of the Ninja Master (yeah- I love my full titles) 
Sonic Spinball 
Sonic 1 
Sonic 2 (the first game I ever owned) 
Sonic 3 and Knuckles (they're rather crap separately but together they make the best Sonic game of all time) 
Splatterhouse 2 
Splatterhouse 3 (completely different style of game- if you don't like SH2, still give this one a try and vice-versa) 
Street Fighter II (not going to name every damn variant- you know what this is) 
Street Racer (a decent Mario Kart clone with some unique modes)
Streets of Rage 
Streets of Rage 2 (my favourite game of all time) 
Bare Knuckle 3 (the uncensored version of SOR3 with far more balanced difficulty) 
Sunset Riders (inferior to the SNES/arcade, but still a great game) 
Super Hang On 
Super Monaco GP 
Super Thunder Blade
The Lion King 
The Ooze 
The Punisher (great Capcom beat-em-up) 
Toejam and Earl (perfect co-op) 
ToeJam & Earl in Panic on Funkotron 
  
Still need to add some up to "Zed". 

I'm going to add to this list and turn it into my first blog.

Great, now you reminded me I have to start building my snes collection again.

Shining Force I and II

Phantasy Star II & IV (you can safely skip III).

Gunstar Heroes
 
Edit: I see now that's a duplicate - it was on the same row as the entry above it in the big list
 
Well anyway, for emphasis.  That game ruled.  (SoR II is amazing as well)