For sheer diversity, the obvious answer is the PS2. However, I find myself liking the Xbox's catalog more and more. Not only does it have a ton of quality PC ports (which basically means I can get by without a gaming PC), it also has the best versions of all last-gen cross-platform titles (most such titles look downright ugly on the PS2 in comparison), and a good number of exclusives in its own right.
The only catch is that most of its library is limited to Western games, but I'm not much for quirky OMG KAWAII ^___^ Japanese stuff anyway (except for Katamari).
"'Casual games' are something the 'Game Industry' invented to explain away the Wii success instead of actually listening or looking at what Nintendo did. There is no 'casual strategy' from Nintendo. 'Accessible strategy', yes, but ‘casual gamers’ is just the 'Game Industry''s polite way of saying what they feel: 'retarded gamers'."
-Sean Malstrom
