hi there mate! 2wd is probably the more common choice of racing, although 4wd seems to be on its way back up...
id say go for a 2wd car, less maintenance, less demanding on your batteries and other equipment etc etc.
if you have a rough idea of budget? then many people will be able to advise on what is best to buy, some people may even be selling stuff in the "for sale" section on here....
tell us what you want from the car and a rough budget to spend and most will point you in the right direction.
hope this helps
feel free to pm me if you need any more info or w.e
also good point from jim there, check out what your local track races most!
Tom