Is REST the Best?

I’ve been reading up on web services lately (I’m gong to be taking a class soon and I want to be prepared), and I keep coming across the REST (Representational State Transfer) concept. Some sites say that REST is the answer, others say REST needs to be combined with other technologies (SOAP, XML-RPC, etc.) in order to get the maximum effect.

Perhaps I’m asking this question too early in my reading/research, but are there any success stories of REST being used without the other technologies? I know that sites like del.icio.us are using REST (along with either Google or Yahoo for accessing their web services, I can’t remember which), but I’m wondering if there are any stories of enterprise/commercial sites that are using REST successfully. I’m curious to see what pitfalls and benefits they ran into. Anyone have any good links?