In reply to samparsons:
I thought i'd have a stack of reccommendations but I just checked my logbook and was surprised to find I have only ticked 2 7b's on the whole of Portland! (delusions of grandeur I guess)
As above, Want Out is a good, technical climb but hard in the grade, the other route I have ticked is Spanner Eyes at Blacknor north, another fine route and a bit easier than Want Out, plus it gives you a good reason to do Englands Dreaming 7a+ right next to it, a real stunner.
I've also been on Twangy Pearl and thought it was pretty decent, I do plan to get back and tick it one day, it does have quite a bouldery crux from memory, so might be a bit tough for a first 7b.
As Sam says above, what sort of style would you prefer?
Personally I thought Zinc Oxide Mountain was a country mile away from 7b, it took me years to get it ticked! But it is one of the best routes on the island and well worth an attempt regardless, you'll love it.