I play guitar, but I always like the sound of the clarinet, I was thinking of getting one. I don't play a regular Clarinet, but I do have a pocket clarinet made of Ebony and I love the sound. I always heard that the old Clarinets made of Ebony had the best sound, but some point in time they stop making them out of Ebony wood, now most of the use Grenadilla wood, some other exotic woods are used too (I can't think of them off hand.) Ebonite (Hard Resin), ABS Plastic are also used.
I found this site saying Grenadilla wood isn't the best, but his pick, Rosewood, has too many problems inherent with the wood.

The Grenadilla Myth
http://www.ridenourclarinetproducts.com/grenadillamyth.htm

So what is the best material for a Clarinet? (Best in sound, & overall durablity.)

From what I have heard, an expensive plastic clarinet will sound better than a cheap wooden one.

A lot of Clarinets are made out of Grenadilla wood, I think most or all of the Buffet line of Clarinets (the wooden ones anyways) are made of that.

Ask your music store if you can try out the different Clarinets they have, and decide for yourself.

buffet also makes "greenline" clarinets, which i think are a mixture of grenedilla and resin? not sure. i've only played plastic and grenedilla, and the quality difference ignoring materials (vito versus buffet) make my comparisons pretty useless as far as materials go :P