Generically, yes, Resto is the most needed, but not because people need a Resto Shaman specifically; most people are just short on tanks and/or healers in general.
There really isn't a spec out there that's going to guarantee that you're going to be able to do whatever you want whenever you want. My guild right now needs a couple good DPS and some more healers, but they've already got me, so they're looking for Druids, Paladins, and Priests. We'd take an Enhancer or Elemental, but not a Resto at the moment.
I'm with Nocturnal on this one. Just pick the playstile you like the best and dedicate yourself to being as good at it as you can. If you are, people will take notice and will seek you out.
Nothing will help you so much as getting into a guild and solidifying a spot there though.