I love sambar stag. Damn stuff is getting hard to find and very expensive, but as far as I am concerned it is worth the money. It can move and crack and needs to be cared for, but with a little effort it will last longer than you will.
Another material I love is sheep horn. This one does not seem to crack as easily, but can move as it dries, and if you live in a very humid area it can actually pull apart.
I love some of the hardwoods and many burls. These should be stabilized, even the hardwoods, and yes you can stabilize Ironwood and Snakewood. The burls must be stabilized as they would not stand up well to use otherwise.
Bone is OK, but not a favorite of mine. I find it boring. It can be dyed and when done the way Bruce Evans does his it looks quite a bit like mammoth ivory. He really does a great job. Jigged bone can be nice on the right folder, but stag is much nicer in my opinion.