I voted for the Mega Drive though the PS would come a close second.
The Mega Drive was the first console I ever owned after years of Sinclair Spectrum action. I've still got my original machine from '93 and still collecting games for it when I can afford them - up to 36 at the moment but the back catalogue is a few hundred. Got the Mega CD add-on a few years back and have 10 of the games for it including Snatcher made by the same people behind Metal Gear Solid. If you check out eBay, you'll see how sought after that one is. Loads of great games on it besides that though like Final Fight, Sonic CD and much enhanced versions of MD games like Earthworm Jim and Ecco the Dolphin
I love all the consoles new and old though. If memory serves, I got an original Gameboy a year after the MD, which again I still have. Not a big portable machine fan, though you can't fail with Tetris. Got a PS the following year at launch with Ridge Racer, which I wish I'd kept as the original version's much sought after by audio people apparently due to the quality of the sound it produces. The PS would've never existed if it weren't for Nintendo though as it was an off-shoot of an add-on Sony had designed for the SNES that never came to fruition. Sony and Nintendo had a falling out and that's how the former essentially went into the console market and one of the reasons why the PS pad is so similar to that of the SNES.
A year later, I also got an N64 though I never really got too many games for it. GoldenEye64 though was and is truly awesome especially when you have 4 players.
Anyway, due to how much I adore(d) the PS, I was a true Sony fanboy. Got a PS2 phase 2 (integrated network adaptor, IR receiver but did away with the optical out) and loved that. Got nabbed during a burglary though and replaced via insurance with a crappy slim version. Sucked even more as they nicked the memory card with my completed GT2 save and the like on it.
Traded that slimline PS2 in for my current 60gb PS3 and love that to pieces. Saying that, backwards compatibility isn't what it's cracked up to be so sourced another phase 2 PS2 from my sis, which I've got about 35 games for and still playing my way through. Bought a SNES a while back too for bugger all cash, including Street Fighter 2 and Starwing. Also got tempted by GameStation's GameCube deal and bought one of those for £15 and paid a tenner on eBay for both Metroid games.
I've built up an okay collection so far but would love a Neo Geo AES as well as more of the Sega consoles like the Saturn, Dreamcast and the like. I may consider getting an XBox at some point as well :wink: