I bought a xbox 360... but the ps3 will be my primary system.. because, the online is free w/ the ps3, I rather now spend money for the MS Live service. Also, the ps3 will be my primary, cause the xbox 360 gets too hot, I don't want to use the 360 for my primary system, and put it at risk of over heating.
My point is that the ps3 is good purchase, casue the system is durable, and if you got a game released on both systems, then I'd pick the ps3 version (most of the time).