Out of the two, I would say the XBOX 360. Yes, the PS3 is a Blu-Ray player, however the 360 has the X-Box arcade which allows you to download more games, most of them classic's.
However, for easy play and overall better value, get the Nintendo Wii. It has a bigger variety of games, plus the downloadable content has something for everyone. Plus, it comes with Wii Sports packaged in, which has Bowling, Boxing, Tennis, Golf and Baseball.