My daily users are all micarta 21's. Love 'em. They'll probaby toss one in the box with me when it's all done.
That said, my favorite are wood inlays, especially the lighter ones like box elder and splated anything. I don't own many 31's, but I do plan to pick up a used large 31 Insingo box edler some day. They didn't do 21 Insingos or stonewash with wood from the factory that I ever saw back in the day, so it's kind of a grail to me.