Currently playing: just started Skies of Arcadia (Dreamcast), and there a couple of others that I'm kinda/sorta going through (Front Mission 4, Mega Man X: Command Mission, Final Fantasy Tactics)
Biggest waste of money: Nintendo 64. Only ever bought two games for it (Mario 64 and StarFox 64), and it actually spent more time in other people's houses than my own, because I loaned it to people a lot. Oh well.
Favorite games: just about any Tetris game, GT2 and GT4, most Tony Hawk's Pro Skater games, Earthbound, StarFox & StarFox 64, Music Generator, Shadow of the Colossus, ICO, Katamari Damaci & We Love Katamari, Tourist Trophy, Final Fantasy VII & Tactics, Bomberman series, etc...
Most hated/pointless/frustrating games: Back to the Future II & III, Low G Man, and others I can't remember because they're not worth remembering.