So I see that MVC 2 now supports [HttpPut] and [HttpDelete] as well as [HttpGet] and [HttpPost], making it possible to do
I can't talk for the MVC toolkit, but personally I find WCF a pain to work with. It does have uses, but it's quite a heavy framework and can be quite awkward to use at times.
If you want to go down the REST route, OpenRasta is the best .Net solution currently around. Especially in terms of compliance.
You can also forge the ASP MVC framework to be RESTful, but that requires a fair bit of work (compared to OpenRasta which works out of the box).