I use my Xbox more than my PS2 because of XBL, better 4player games for my friends and I, the xbox has the better version of multi-platform games (so I always get those for my Xbox), HALO and DOA3 (it's insane how much play time these games get from both multi and single player sessions) and quite frankly I prefer more of the Xbox exclusive titles such as Crimson Skies, Halo, DOA3, RS3, RTCW, Panzer Dragoon Orta, etc....
When I do play my PS2, I use it for those beat 'em up games such as Devil May Cry, Rhygar, Castlevania Lament of Innocence and Chaos Legion. I also use it for 4Player Smackdown Tournaments with my friends and I. The RPGs on the PS2 are plentiful but I find most of them being very mediocre or bad rip-offs of other RPGs, so basically I invested most of my RPG playing time with FF-X and the .Hack series.