Hmm.. I'm not quite sure.
If you're talking about grown women then Tsunade is probably the best choice... she is incredibly strong and can pretty much destroy entire buildings with a well placed punch. Add that to her amazing healing abilitys and regenerative jutsu she's almost invincible. Plus she was the Hokage, that's gotta count for something.
But then there is Sakura, Tenten and Hinata, if you're talking about girls.
Sakura is like a mini-Tsunade except she's already incredibly strong and her healing abilitys rival Tsunades, plus she's still young and learning so she can only get better.
Hinata was much stronger that Sakura tough in Part 1, and she seems to be faily competant in healing as well. Hinata has all the dexterity and precision that her clan jutsus require and just as Sakuras improved so as Hinata. If they both improved at the same rate than Hinata is the clear winner.
Tenten is the direct opostie to Sakura and Hinata because her attacks are long range and if she could keep her distance during a battle then she'd demolish them, well... maybe not Hinata because her Byakugan might give her an advantage and enable her to dodge but otherwise Tenten would kill them both seeing as she was probably stronger than both of them during Part 1. Another thing is that Tenten is probably good at hand-to-hand fighting as well, I cannot see her sucking at it when she is on a team with three hand-to-hand masters.
One of them ^^' I cannot choose.