Instead of worrying about the hardware issues and games, I would concentrate on the social connectivity differences in relation to what he wants out of game. If he wants a bulletproof unit (so far, but there also a lot less of them out there) go with the PS3. If all he wants to do is play Madden, then it will be fine.
If he is wanting to play online with a group of friends (not such an issue with Madden), then Xbox Live is the cat's pajamas. Sure, it's 50 bucks a year, but constant updates, friends lists, achievement scores, voice chat...it's great. As a matter of fact, because of Xbox Live I get to play with and talk with my best bud up in Detroit 3-4 nights a week.
Now, the can of worms... If you aren't hooking it up to an HD TV, then don't worry about which looks better. Also, this "raw untapped graphics power of the Cell that will not go obsolete for 10 years" that Sony claims is bologna. I'm not the guy to explain it, but that's the kind of work that my buddy in Detroit does. After putting his head together with a bunch of other nerds, they (in their opinion, of course) feel that graphically the 360 and PS3 are going to be neck and neck when it comes to graphics for years to come. Of course, some of them are anti-MS (man, do they hate Windows

), and will buy a PS3 just on principle.
What is going to save the PS3 is their exclusives...if they can keep them. Metal Gear is a big one. Also, SOCOM has rabid fans that bought the system just for the game that doesn't have a release date yet. Of course, keep in mind that many exclusives for the PS3 have come to the 360. Assassin's Creed? That was to be an exclusive on the PS3.
I guess it boils down to this: If he wants a pretty gaming system for just a few games, then the PS3 will probably serve him well. If he likes a lot of social interaction and community and First Person Shooters, the 360 abounds.
Also, Halo is extremely overrated in my opinion. I played 1 and 2 on my old xbox and bought 3 opening week...meh. Not tactical enough for me.