Lets try some ladies from Scrubs:

Dr. Molly, the short lived shrink.

Dr. Elliot Reed, neurotic private practice doctor.

Nurse Carla Turk, know it all Dominican head nurse.
Ok, I will gladly say that I would kill our shrink. She's way to flaky to marry. And I think her penchant for 'broken' men would leave any bedroom activity rather cold.
Next I think I would boff Dr. Reed. This was tough, but I think Elliot's neurosis would drive me nuts for the long haul. but could lead to some heavy duty passion for a one time deal.
Leaving Carla to marry. Which is probably the right choice. Her take charge attitude could whip me into shape and based on the episode where she tries to hold a sex embargo (and fails because she can't hold out), I wouldn't have to worry about the sitcom sterotype of 'no sex once you're married'.
So, what say you folks? It was a fun exersize for the 10 minutes it took for me to type this up.