Damn, the more I think about it, the harder it gets. If I had to choose, I guess the Gamecube, because my #1 favorite game is there (Skies of Arcadia: Legends) and another top 5 (Sonic Adventure 2: Battle, which is pretty much infinitely replayable), there's a Fire Emblem, one of the best Zeldas and another that's pretty good, Smash Melee, Thousand-Year Door, Soulcalibur II if I want another fighting game, several Sims games that are good even if they aren't a perfect match for their PC counterparts, at least one great Mario Party (4) and some okay ones, the last good Star Fox games that weren't just regurgitating SF64... yeah, I think I probably still like the Gamecube's library the best for my tastes if I could only keep one console.