Career: Ray Allen. This season that is really tough though, I like taking into account a large amount of attempts before crowning someone as the 3 point champ. Matt Bonner is leading the league this season in percentage, but everything else being equal I'm not sure he would flourish everywhere to that degree.
For this season I'd take Morrow, or at least include him on the list. That kid's shot is pretty, too bad he can't do enough else to stay on the court.
Definitely Jason Kapono. The dude's got nothing else to his game, which makes it easier for opposing teams to defend him. But if he's open and remaining a set shooter (instead of trying to dribble around like an idiot), there's nobody who's more likely to hit a 3 pointer.
Peja or Allen. Peja if he never got injured, And Allen if he wasn't a superstar (and thus got superstar-level attention from defenses)
I'd say Ray Allen. The dude is money, plus his ability to drive and pass is very good for someone who is known for his 3-point shooting. Kapono is a close second, with Kobe third.
House because before he catches the ball, not even a second and then releases it. (faster release in nba I'm pretty sure lol)