Ristamar said:
I do agree, though, that the XBOX likely has the best HDTV support, from what I've heard.
Some of the Xbox titles will support up to 720p, which is patently insane, but there it is.
Ristamar's summary was pretty much spot on. PS2 not only has a large selection of titles, but the largest installed base in Japan, where XBOX has yet to land a significant dent.
However, the PS also had hundreds of games, and lets not forget that hundreds of those games were TERRIBLE. Sony's signal-to-noise ratio was and continues to be terrible, in this regard. For every MGS2 and Devil May Cry, you'll find five Summoners, Monsters, Incs and Shadowman 2s. Some of those games are so cheap for a reason.

Nintendo, on the other hand, produces fewer games, but on the whole they are usually of a higher caliber. Sure, Mario Sunshine is just more Mario with better graphics....
but since when is that a BAD thing?
Despite some folks anti-MS sentiment, one Xbox strength is that Microsoft is actively acquiring developers to grow their software community. Rare, Bungie and Sega are both forces to be contended with. The Xbox being similar to a PC seems an odd thing to consider a negative, frankly. Consoles and PCs are more alike than different, and arcade machines these days even more so. I would consider this a strength, since it means more plug-in developers for Microsoft, but with a guarantee of assumed hardware.
Ultimately, the deciding factor should be what type of game you enjoy, and where you can find it. Sony has the largest installed base, and that translates into many games coming their first. Currently, more innovative titles seem to appear on Sony. Sony also gets more RPGs by far. Nintendo consistently produces more family-friendly titles (note I didn't say 'kids games'...just games that I can play with my kids in the same room). Xbox is still finding it's feet, although games like Splinter Cell and Starcraft:Ghost certainly look very nice.
Ultimately, there is no wrong answer. As long as you have fun, you've won...and all three offer that in some capacity.