That's always an option too. Graphics (on the whole) are better on the xbox and there are some HD games if you have the setup for it.
That said the difference is not so great that you will hate one or the other. Find the one that has the games you wan to play and go with that.

PS I have both. If the game is out on both I buy whichever seems to have the most extra stuff.

jr

"What can be asserted without evidence can also be dismissed without evidence." C Hitchens