I have both.
yes, you have to pay for 360 online stuff and ps3 is free...but it shows. the online experience for xbox is light years ahead of the ps3 online experience.
if a game comes out for both the 360 and and ps3, i will always buy the 360 version hands down. all of the extra features they add to the ps3 always feel like add-ons, rather than being integrated like they are on the 360. take netflix streaming for example...on the ps3, in order to get netflix streaming, you need to send away for a special disc, and the disc must be inserted into the ps3 whenever you want to stream netflix. totally ass backwards.
having blu-ray in the ps3 is nice, but the future of movie watching is digital distrubution. that being said, for games, it can be a bonus since you can fit a ton of more content, and publishers are not always willing to ship on more than 1 disc for the 360 (i worked for a game developer for 3 years...released a game for the ps3 and 360). horsepower wise, they are about equal.
but when it comes down to it...take a look at system exclusives and buy the system that has the most that you want to play