I used to own an xbox 360 and have spent hours playing a nintendo wii and was not entirely satisfied , so i bought a playstation 3 and found that it has a much better set up . The whole thing is made better , build quality ,looks ,free online and so on. The only problem is that game developers dont understand how to properly make games for it yet. Games come out and dont look finished , graphics dont live up to the hype, eg GTA4 , CONDEMNED 2 , with the exception of COD4 , which looks amazing by the way.
I can honestly say that the ps3 is the best of a bad bunch of new consoles and this is why.
Nintendo wii = Last gen graphics , babyish games , awkward controls and limited online capabilities.
Xbox 360 = unreliable , be prepared to wait for your xbox to be repaired after a few weeks , it will break! ,online is not free and does not have the advantage of a blue ray player , which trust me will be a big thing in the near future.
PS3 = Free online service,great build quality , reliable, great future exclusive games , blue ray player , but has lazily developed games on the market which just dont really impress as they should do .
So after all that I think only the ps3 can improve in the future [when developers pull there fingers out of there asses] and the 360 and wii can only get worse , go for the ps3 its the best console out there , but only just!