It all depends on what kind of games you like to play. I usually plug in the psx or dreamcast if I want to kill an hour having mindless fun. The games I play on the main PC are usually best with a few players on the internet and sometimes are more effort setting up then I feel like doing at the time.
Most of the single player games I get into are old dos games on my old dos rigs, and the older amiga/c64 stuff.
But there are a ton of fun games on the psx and dreamcast, not sure about the psx2 since I dont have one yet. Once they are $100 or so I will get the psx2 and probably the xbox also.
Sonce I have more games then i can play now I am in no hurry, that and you need a dvd-rw to get the most out of the newer consoles unless you have alot of uneeded cash (and I dont at the moment).
Latest and greatest doesnt allways mean the best.