kimbo, i know that you have posted this topic for us to answer. but just letting you know, because you have surfed and do wanna get into waves, go into windshack in north freo (windshack.com) and talk to alberto, he wont lie to you, and will definatly point you in the rite direction. he has helped me out heeps. at the moment he hasnt got much a bigginers type board, second hand,. but he has a whole lot of knowlege, and will tell you exactly what you need to know and some more about how the sport in changing and what you need to look out for, etc etc..
any way for my point on this topic.
if you wanna get into waves eventually, i would try get a board with a nice rocker line. just so you have the opportunity to take it into small waves or big chop. this way you will get a little bit of a feel before you need to go buy a wave kit. for an example of a board like this, i would recommend a starboard carve, 130 to 160 liters, but only if you have good balance, the carves have a nice volume and a little bit of width to them but still you will need good balence for this board.. another board wich is good for beggining on (but not to bring into ocean) is the starboard go, i have both of these boards i mentioned, and i love them for going into the open river, where you get really good speed, this board isnt just for learners, its for light winds, and just speeding around, getting your gybes, tacks, down. another thing is to get a board with a tough skin to it, dont go for hard fiber glass carbon type things because you will end up spending more on repairs than you did on the board, with all the slams your gonna have, especially when you get to your harness