I've also got both, but prefer the PS3 by far. To give you an idea, I have about 62 PS3 games and only 5 X360 games. Each console has its pros and cons, but I think in the end the most important thing to consider is which of the exclusive titles you want to play the most. Obviously, as others have stated, most multi-plat titles look/perform better on the X360, but the excellent PS3 exclusives more than make up for that IMO.
The PS3 exclusives pretty much put the X360 exclusives to shame. Sure the X360 has Gears of War, Halo, Forza and a few others, but the PS3 has Uncharted, Killzone, Heavy Rain, Little Big Planet, inFAMOUS, Resistance, and a lot more. PS3 is also getting The Last of Us, which X360 is not. If I didn't have either console and had to choose now, I would get the PS3 purely based on what I have seen and read about The Last of Us.
While I will agree that Xbox live is a better service, it costs money to play against other people (which is ridiculous IMO) and therefore I prefer PSN. Blu-ray is also a huge advantage. Not only will you be able to watch blu-rays, but your discs won't get scratched (easily, like X360 discs) and some games that come on multiple discs on X360 will fit onto a single blu-ray, thereby eliminating (irritating) disc-swopping.
Another thing to consider (if you're into motion gaming) is whether you prefer Kinect to PS Move. Personally I prefer the Move as I like to have something in my hand when I'm controlling what's on the screen. The Sharpshooter accessory also works great with games like Killzone 3, Resistance 3 and House of the Dead: Overkill. IMO Kinect is purely for kids/casuals at this stage whereas the Move caters for casuals and hardcore gamers alike.