Vapor barrier required???

If I'm using a shower surround over greenboard,do I need a vapor barrier between the studs and board? Or should I forget the greenboard and use cement board? I have to admit that looking at all the different threads,I get more and more confused on what to use. Your opinions and suggestions are appreciated. Thanks

What type of surround are you using? Glue to substrate or attach to stud / wall?

Its one of the 5 panel glue on kits I bought at HD. Going over an insulated wall. This is it,
http://www.asbcorp.com/subcategory.cfm?subcatid=79
Should I go a different route, or is this OK? Some opinions before I get started on the shower/tub area are appreciated. All there is now is studs with insulation inbetween. If the vapor barrier is needed, whats best to attach it with, staples? Tks.

I've never used a vapor barrier when installing a fiberglass/plastic shower surround. When installing tile or other material that water can go thru then I definitely use a moisture barrier. A properly installed shower surround should stay totally dry between it and the drywall...therefore, no vapor barrier should be required.... just make sure it is sealed real good. Using a semi-gloss paint in the bath gives a much better seal than flat paint. Good caulking and caulking techniques will keep things dry...and caulk needs a little maintenance over the years.