Combat is made for PvP. I leveled as Combat, the burst is amazing. The roots are awesome.
For low levels put 3 point into the watchman tree skill that refunds focus (sorry forgot the name off the top of my head), then start working your way up the Combat tree. Skip accuracy for now - fill in a point or 2 if you need it at 50, practically every other skill is useful for PvP in the Combat tree.
Just work on getting to blade rush as soon as you can, you really can't go wrong.