First, you need to ask yourself some questions:
1) How much do you care about Blu-ray movies? Whether or not Blu-ray is really "that spectacular" is a matter of opinion. I consider it a videophile format - basically, if you're a movie fanatic and care a lot about picture quality, then Blu-ray will be a big deal to you. If you're not, it really won't matter much. In any case, if you don't have a Blu-ray player and decide you want one, PS3 is the way to go.
2) Do you have a high-end gaming PC? The 360 has quite a few high-quality "console exclusives" - 360/PC multiplatform games. If you don't have a high-end gaming PC and don't plan to get one in the near future, 360 is probably the way to go.
3) If you don't care about the Blu-ray functionality of the PS3 and have a high-end gaming PC, then it mainly comes down to the true exclusives and the price. Exclusives is all personal preference; you'll have to figure out for yourself which games interest you most. As for price, the 360 will probably be cheaper. However, if you need wireless network access, the adapter is expensive for the 360. That alone can erase the 360's price advantage.
