Hello,
Some good places to start:
Brahms clarinet sonatas (1 and 2)
Brahms clarinet quintet
Mozart clarinet quintet
Mozart clarinet concerto
Weber clarinet concerto and concertino
These are very standard repertoire, so there are many artists who have recorded these pieces. Some that I like are: Charles Neidich, David Shifrin, Sabine Meyer, Harold Wright. Richard Stoltzmann (sp?) is also excellent, but his tone is very different from most American and European clarinetists.
Lucky me, I'm actually playing the two quinetets (as a violinist). It almost makes me wish I kept playing clarinet. Speaking of which, are there any other wind players on this board? I know there's a couple of other fiddlers.
Walther