I have yet to find a need for writing a CLR package of any kind, so I'm not using CLR directly.

However, I do use CLR quite a lot. We have more and more apps taking advantage of the spatial data type.This is a CLR data type and the functionality it provides is through CLR.

I know that Adam Machanic has found some places where CLR is doing amazing stuff, but you'd need him to detail it where he can.