I like to play as the Count of Carcassonne (part of France), personally.
In 1066 you start with two provinces (Carcassonne and Montpellier) which have a good little income, so you can build them up quite quickly. You're also right on the Mediterranean, giving you easy access to Muslim Iberia and Africa, so ample opportunity to expand.
The only downside to this dynasty is that your starting ruler is married to his own niece, so you may get some inbred children. I've been lucky in the past and the inbred trait has been confined mostly to female children, but if you get an inbred heir you may be in for some trouble.