I just got the 360 a few days ago and it's amazing. The graphics on this thing the best I've ever seen on a home system and the games I've played so far are very cool. This system is also a great buy at $399.99 (HD Included) compared to the rumored price that the PS3 will go for this fall ($499.99-$599.99) not to mention you won't have to worry about something Sony is rumored to be thinking of doing:
Making trading in your used games restricted. Rumor has it Sony is gonna have it to when you buy a game...you're just paying for the license and they actually own the disk making it illegal to sell it to places like EB Games etc. The jury's still out on the Wii so only time will tell with that thing. However, if you want a cool system with great graphics and games then the 360 is the way to go. You won't be disappointed with your purchase.
P.S. Do yourselves a favor and get the one for $399.99 it will save you money in the long run.