I would say it really depends on what he likes.
If he likes knights, chivalry, i would say bretonnia (but very expensive those days). If he likes fun and monsters, orcs and gobs.
If he likes dwarves, etc...
I would say, anyway, that High-Elves would be a good idea, for the army is one of the easiest to use i think. Orcs are fun and easy to play too.