Hehe, HD is full of fun if you can stand his mediocre abilities. I took him all the way through my first game, however, and felt his contribution to the party was pretty good.
I think a character like HD is best used with hit and run tactics. I gave him the boots of etherealness, Ilbratha, a ring of invisibility, and the belt of inertial barrier. I kept him near the back and only sent him into melee after all opponents had attacked my fighters.
Otherwise, he was pretty much the only reason for my clerics to memorize heal spells.
Oh, and his romance with Aerie is not only mildly amusing, it seems to dampen her whining and eventually turns her into a stronger (emotionally) character.
Maybe I kept him because as the only other male in the party he helped me keep track of whose battle cry was whose.
