When I graduated college, I received nothing but cash. And I think thats what he would like best. It is hard to think of something right on the spot that I want, but then I see it somewhere and then I remember.
Other things I liked that I received from people who didn't want to give cash: Itunes Gift Card, Costco Cash card, or maybe just like an Irvine Spectrum cash card.
Another nice idea is maybe a subscription to blockbuster online. I got both my sisters (they are closer to 30 though) a 3 month subscription to that for Christmas last year and they loved it. After thier 3 months was up, they got their own subscription and still have it now.
I think a cool idea would be something that gets him started at a nice restaurant like Morton's or Ruth's Criss (I'm a steak guy). Sure he may have to pitch in some of his own money if he brings a date, but at least that way he'll find out what its like. I never went to those places growing up and would probably still never have experienced what they are like without someone giving me a giftcard first.