Mortal Kombat sold me on my Vita. What games convinced you to buy a specific platform to play them?
Demon's Souls is what originally sold me on buying a PS3 (though having my 5th Xbox break really helped...)
I bought an Xbox this past Christmas because I really wanted to play Gears 3 and Halo Reach, but I really kind of regret it and am thinking about selling it.
Halo is why I chose an Xbox and Metroid Prime is why I chose a Gamecube. I had other games I wanted on those systems before buying them, but the games mentioned were the main reasons I bought their respective consoles.
I got a PS2 because I couldn't pick out just one game that I wanted to play on it. Everyone needs a PS2, it's *almost* as essential as a Super Nintendo.
i bought a 3DS for Mega Man Legends 3 but that never ended up being a thing. hopefully there will be more games for the 3DS in the future that catch my interest because right now it's just collecting dust, making me wish i didn't buy a 3DS. i also bought a 360 to play Dead or Alive 4, and that ended up being the console i mainly play on.
I bought (or rather asked my mum to buy for christmas) a ps2 primarily for RE: Code: Veronica X. Which was the same reasoning behind me getting a gamecube, with RE4, RE0 and the remake.
EDIT: Also, should the rumour about there being a new story-driven RE game starring Claire Redfield upcoming on the 3DS (to go with Revelations of course), then I'll follow the same routine...
Fortunately, I of course do buy other games down the line for the consoles; i.e Eternal Darkness, SSBM, Luigi's Mansion, Tales of Symphonia ect. for the gamecube. But it's usually RE games that force me to make the first step.
EDIT2: Oh! And I remember now that I got a 360 for the GTAIV expansions. My PS3 I bought for no one game in particular and just wanted to catch up into the next generation.
DOA3 is what got me to buy an Xbox, Lumines (and to an extent, Wipeout) got me to buy a PSP, Tekken got me to buy a PS1.
I can't remember what motivated me to buy the other systems. PS2 I got pretty much at the end of the lifecycle for the system, and I'd been buying games I wanted to play for a while for it, so I guess at some point it just hit critical mass.
I bought a PlayStation 1 for Grandia. I was a SEGA fanboy, and Grandia for the Saturn never came out in the West.
I bought a PlayStation 2 for Dragon Quest VIII. DQ7 was amazing and I had to play the sequel.
I bought an Xbox 360 to play Modern Warfare 2 with my friends. We played it twice, I think. It has some other great games though. :)
If Fire Emblem: Awakening comes to the states, I will willingly and happily put down whatever cash money is necessary to purchase a 3DS and even perhaps purchase some other software titles as well.
Obviously, if we aren't talking prospectively, then I got my 360 when Mass Effect came out, being the Bioware fan I was.
I have never done it before, usually just wanted the console and got a few games to play on it but GTA IV pushed me to get a 360 and I was dying to play MGS4 for two years after having played the first three
hadn't paid much attention to this generation until the GTAIV trailer
NES for Mike Tyson's Punch Out.
SNES for Final Fantasy 2
Atari Lynx for a proper version of Rampage.
Neo Geo for Samurai Spirits 2.
3DO for Return Fire
Playstation for Resident Evil.
Saturn for Guardian Heros.
N64 for Smash Brothers.
Dreamcast for Power Stone.
Game Cube for Pac-Man Vs.
Xbox for Halo.
Haven't bought a console since, as the hardware became junk, greedy collector's editions that provide garbage and fluff, High console game prices while providing less value/content like no more nice booklets / cheaper thinner cases, game content cut for $DLC, and more restrictive DRM that assumes paying customers are criminals.
PC only since 2004 and Viva la Steam!!!
Super Smash bros. Melee and Metroid Prime for the gamecube
My brother and I got our first xbox because we knew halo 3 would come out for it, then oblivion came out too. We got it early on; there weren't many great games out yet, but we knew there would be.
Super Smash Bros. Brawl for the Wii
Demon's Souls for the PS3
and Pokemon White for the NDSi.
I got a new Xbox in england for Skyrim, I also needed a console for when I wasn't at home, since I no longer live in Spain.
It's a bad idea to buy a console for one game in particular. Taking into consideration on the consoles I purchased with my hard earned money, I purchased the Gamecube and Xbox 360 because they had established libraries full of quality titles. I bought a GBA for the same reason. I bought a DS and PSP on launch day with faith that they would eventually have great games. I haven't bought a PS Vita because I don't expect it to ever have a very strong library, though there are some enticing individual titles.
Ok, so I totally bought a PS3 for MGS4 and MGS4 alone. I didn't really care what else was on the console. I don't want to ever do that again, though.
I absolutely think that one title can be the catalyst that drives you to buy a console you've been considering. I won't buy the PS4 at launch, but as soon as Final Fantasy XV comes out, I'll buy it, as long as it has a good library.
Oh, who am I kidding. I would probably buy a console just for FFXV, even if it sucks.
I really can't recall what made me buy most of my consoles. Back then it was just wanting the newest thing because that's what they made games for. The only ones I can recall are the Gameboy Colour for Pokemon Red, and my PC for the Command and Conquer games.
Sonic the Hedgehog - Genesis/Mega Drive
The Legend of Zelda: Link's Awakening - Game Boy
The Legend of Zelda: Ocarina of Time - Nintendo 64
Soul Calibur - Dreamcast
Super Mario Advance - Game Boy Advance
Super Smash Bros. Melee - GameCube
Halo: Combat Evolved - Xbox
Metal Gear Solid 3: Snake Eater - Playstation 2
The Elder Scrolls IV: Oblivion - Xbox 360
Metal Gear Solid 4: Guns of the Patriots - Playstation 3