Raeba, there are so many knives to choose from these days, I just have a dresser drawer full to satisfy my cravings for sharp stuff. For most folks, I would stay away from serrated edges. They are problematic for sharpening for MOST people. Not everyone has the tools needed to get those little edges properly sharpened. As to recommending individual knives, that's easy. I agree with about everyone on here, Benchmade, Spyderco, Buck, Columbia River, and a few others for folders.
I am including a few links to some kniuves I have personally. These are the very best both economically, and utility minded folks can appreciate.

http://www.crkt.com/M21.html
http://www.crkt.com/litem1.html
that Lightfoot M1 is a little thick for some, it's a TOUGH folder and has a GREAT edge and steel is real good. AUS 8 steel is what lots of companies use. It's easy to sharpen, and keeps a good edge.
The Benchmade Griptilian is a good all around knife as some suggested. There are a couple different steels available on those, but it really doesn't matter. I could sit here all day and tell you this stuff and offer suggestions. Several others suggested for you to let him pick out his own, that knife guys are picky, but the thing is if you buy it for him, he'll love it, no matter wht it is. Good luck.