What qualities the new leader, I think, should have:
1. represents the new generation of Palestinians, and is not from the Old guard of Arafat's era, who most of them have lost the support of Palestinian people.
2. Strong enough to stand by the basic principles that Palestinians want, and not give into Israeli and American pressure.
3. Have the support of the majority of the people.
4. Be willing, if necessary, to negotiate.
In my mind, there is only one candidate: Marwan Al Barghouti. He fulfills all of the above criteria, and he has the added bonus of speaking Hebrew (learnt while in Israeli jail). There is one snag, however. He is serving five consecutive life terms in jail at the moment (although there are rumours already circulating that some sort of deal might be struck where he is freed to become leader). Good news is he is considering running. If he does run, there is a strong probability he would win. I think he should. It would send a clear signal to the Israelis that you have jailed (after a political trial) the popularly elected leader of the Palestinians. If you are serious about peace, set him free.