For the most part all the Xbox games if seen have a good PS2 counterpart, though the same can't be said vice versa.
And if games are what's important to you, the PS2 has the biggest installed base, so it's going to have a massive library, sure there's a lot of crap, but there also a ton of kick-ass games.
As for the PS2 being left out in the cold in terms of Star Wars games, there's a massive online SW game in the works for the PS2.