Yeah, The truth is, both systems might end up being as good as each other. Its just one of them (people are thinking the xbox 360) will ;pull out infront after developers have learnt all the code, etc and know what they are doing.
For instance, Xbox/Playstation 2 games have gotten better graphically, etc as times gone on.
Its only a matter of preference that will come into it in the end, as alot of the games this time round are going to come on both, because publishers are going to love the fact they are so closely matched, and easy to port to. Thats going to be a shame, as we dont really want ports, but its a taste of what IS going to happen, not IF.
So, if you like Playstation 3, get that
If you like Xbox 360, get that...
This is what makes these threads so useless when it comes to weighting. Especially since of the power being almost exact. it'll just be a matter of which developers/publishers choose who for what.