Gameboy, Gameboy, Gameboy, and the Gameboy.
I still have 1 Gameboy color, 1 Gameboy Advance, and 2 Gameboy Advance SP... plus FireRed, crystal, gold, yellow, Final Fantasy 1 and 2 Dawn of Souls pack thing, Fire Emblem, and Golden Sun 1 and 2 :3 Oh yeah, Sword of Mana too.
I do play the NES(Final Fantasy FTW!!!!) and the SNES, my Nintendo 64 isn't that special(got no FF for it) :|
GameBoy, took mine everywhere I went. From Pokemon, the Oracle Zelda series, Dragon Warrior, FF Advance IV-VI, and Megaman Battle Network. Best times I ever had.
Sega Dreamcast. The NFL2K series let us play on-line against real opponents years before anyone else. I participated in 2 full seasons where we played the actual previous years schedual. Crazy Taxi, Jet Grind Radio,Soul Calibur,Samba di Amigo:
these were the best games out at the time. I've never had so much fun on another console. 9/9/99 debuted the best system of its' day.
I did love my SNES and Game Boy, but the Dreamcast has earned a special place in my heart. I came out and kissed a girl for the fist time during a game of Power Stone Wars, spent countless hours with my closest friends playing Vigilante 8: Second Offence, and played Rainbow Six: Rouge Spear on my first date, though, to be honest, that game was only amusing because of how outrageously crappy it was.