Well, I'm not all for one, I see each one with it's pro's and cons...
Sony - It has a nice and wide selection of games, and great for the average gamer. Downside is that it's graphics pales compared to any of the other current generations...
Nintendo - Good graphics, and more or less balanced selection, not much more to say.
Microsoft - Best graphics compared to the rest, although the genre of games is rather... limited.
Sega - Dreamcast was great, too bad it didn't do so well.
Atari - Makes some great games, and it's old age console is great for nostalga!
Voted Nintendo though, since it currently has the games I like (Zelda, SSBM, Sonic) =)