Yes, a good question would be if he\'s looking for online play or not. From the looks of it, he isn\'t very experienced so this is a question mark. Soulgrind listed most of the good stuff, but if the guy is ready for competition.. Quake III would be an obvious (and cheap) choice. It\'s easily the best pure deathmatch-based multiplayer FPS I\'ve played.
(games such as BF1942 and RTCW are teamplay-based)
I tried the Call of Duty demo and felt it to be rather polished, an excellent choice for single-player. Of course, if he hasn\'t played Half-Life.. that\'d be a good place to start for anybody. Great level design, great multiplayer.