There's alot of great things about each console that you should first consider. First the games.... There's alot of great exclusives for both game consoles that you may want to look into. The PS3 has some masterpieces that throw in alot of great cinematic qualities and have great gameplay i.e. Uncharted series, Metal Gear Solid, Killzone. The 360 on the other hand has alot of fun pick up and play games/online. Left 4 Dead 1 and 2, Gears of War Series, Halo Series, etc. You may want to check a list and see which game exclusives are best for you, the 360 is a more casual gamer experience that offers quite a bit of hardcore games but mainly focuses on more online and pick up and play gaming. Ps3, in my opinion is a Hardcore gamer oriented system that offers a few casual and ****** games like Littlebigplanet and Ratchet and Clank series, but does not offer as much of a casual experience as the 360 or Wii.
Another thing you might want to consider is the party/motion gaming on either console. In my honest opinion, I **** the Microsoft kinect, there are only a few games for it and they get really old, really fast. The technology behind Kinect is great but there is a lack of quality in both presentation and games. Yoostar 2 is a great Kinect party game that lets you and your friends star in a pretty decent selection of movie scenes, and I've played the Biggest Loser and Zumba Fitness which are fairly good exercise games, but there is not a huge library for the 360's motion gaming and there is a pretty noticeable lag in the technology that can make the Kinect frustrating at times.
The PS3 Sony move is a gadget I'm not really familiar with, but I was blown away by it. I played Killzone 3 with the Sony Move on a 3d TV and I was simply blown away. It was way more accurate than the wii and funner than the Xbox 360's Kinect, I'm not sure how many games are on the Sony move but I'm sure the library is leaps and bounds better than Kinect.
The last thing you'll want to consider is online play. In my opinion, 360 has the best online experience, games, community and arcade. Ultimately, if you are going to play online, you'll probably want to ask your friends and buy the console that the majority of your friends have. Playing online and chatting with your friends makes for the best online experience.