I've only knit a few socks and they've all been in Kroy... so far. I've got some new yarn arriving Monday from KnitPicks that I can't wait to try out. I hear a lot of great things about Opal, Tofutsies and Marks and Kattens Clown Sock Yarn... all of which I'd like to try out as my sock skills grow.
And now, thanks to this thread, I have more yarns to try. There will be some happy feet in my family this year!