If you like gaming, sure it's worth it. If you're worried about having "good games" to buy right now, then you should probably hold off a year or two. PS3 will be plauged with the same first year woes that all consoles have. 95% of games will be on both PS3 and 360 and look pretty much the same (I'm talking less distinction than XBOX v. PS2).
Of course, if all you play are SoCom, Gran Turismo, Jax, or another Sony exclusive then that's another situation. Although, you'll be waiting a year or two on Gran Turismo unless you want GTHD, which is GT4 with some work done on the graphics.
Games on the shelf at Walmart isn't the only selling point of the 360, either. Again, if you like game, odds are you'll find a lot in the arcade that is fun and cheap. Plus, lots more coming including a online XBOX Live versions of Street Fighter 2, Frogger and Lumines. Geometry Wars rocks. I've probably spent equal time on the arcade titles as I have the shelf titles. Having E3 demos and videos to download during E3 was great. MS has a solid online service that has taken years to evolve. Sony might give it a good shot, but it wont be anything near Live. It might be enough, but I already know Live works well.
In the end, it's a personal decision. I have a 360 and will have a PS3 on launch day. Looks to me like I'm getting a lot more for my money with the 360 unless you take into account the BluRay player on the PS3 which you are paying $200 for. In the end, both are similar when it comes to games...one has a tad more horsepower, one has a slightly better video card. With game development costing what it does now, there isn't going to be much difference unless it's an exclusive title and has Sony throwing money and resources to it. Another reason I like the MS arcade because it gives you cheaper, not as grand games. I think I'm starting to get too old for the games that require a few hours just to learn the controls.