I personally prefer the Playstation 3 over the Xbox 360. I own a PS3 and many of my friends own X360's. To me the PS3 was a better deal because it came with a built-in BluRay player, a big internal hard drive, Wi-Fi built in, USB ports, and on console internet browser, just to name a few of the many perks that the PS3 has over the Xbox360.
The PS3 wins the title as best bang for your buck, in the entertainment and capabilities department.
The games are where the PS3 is a little less popular then the Xbox 360. It's seems the Xbox 360 has more popular and bigger titles being released on it. While the PS3 has a consistent following of platformers, which may or may not lack the popularity of some Xbox 360 exclusive titles.
My un-biased opinion gives the Xbox 360 the advantage in the game department
The costs of the systems vary depending on what you want. Most prices are based on the features the console has and how big of a hard drive it comes with. The prices of both top of the line systems are fairly close, depending on where you purchase them. But most should agree, you do get more "features" on the PS3 then with the Xbox360, right out of the box.
PS3 wins the features contest
Online play is something both systems have in common. While the Xbox 360's Xbox Live has many more players then the Playstions online, Playstation Network, It also costs a monthly fee, which is something that is avioded on PSN. It all depends on the player, either get free online play with less players or pay a monthly fee and get a top of the line experiance with tons of people, im not saying PSN isn't fun or that nobody plays it, but when your friends are on Xbox Live, it kind of sucks.
A close one but, Online Experience goes to the 360. As fair as free online play the PS3 has it all the way.
Overall I would take my PS3 over a Xbox360 anyday, but that's just me and I love Sony..