The advantages/disadvantages for each language have been discussed here and elsewhere ad naseum. To tell you the truth, I didn't research the language decision too much; my rationale for choosing RoR is based on the fact that we have a R(oR) meetup here in State College, PA; that's why I decided to learn that.

In fact, the decision is not (totally) settled yet. My brother is a web developer with five years experience. He is pushing me towards php on Zend (PoZ?), a php web framework authored by the authors of php. For now, however, I am trying to learn RoR just in case he is not able to help me with PoZ.

That being said, I heard that RoR and Python (maybe on Django) is the best for newbies to start with as far as web dev languages go.