I like the objective maps the best and of the original obj maps, i gotta go with The Hunt. My favourite obj map is Normandy Bridge, we play it all the time on our LAN and even though there are some texturing problems, it is the most wide open and at the same time action packed map there is. Besides, I really like infinite respawn, and I don't enjoy omaha very much (the choke point in the bunker makes it almost impossible for the attackers to get past a coordinated defense).
Of the original dm maps I like stalingrad, even though I don't play it any more because the tense situations it puts me in gives me the shakes before I even start playing

(maybe the problem is that on our LAN everyone goes sniper on that map). Of the user created dm maps I like hide and seek 2, if only because of how different that map plays. There really isn't any significant cover, the only thing that stands between you and hitting the other guy is finding him.