Psikus
Explorer
Add to that the fact that you must *hit* to get THPs, thus using a low proficiency weapon (re: hammer) is stupid.
Well, you will have a ton of Con, and barely any Dex. At paragon tier, that means you can get Hammer Rhythm but probably won't qualify for Heavy Blade feats. That's a pretty good incentive. At epic, a longsword might force you to sacrifice the weapon mastery feats, which will hardly be optimal.