Hi Peter
I'm a convert to the WoWo lambswool mitt. I have both the thumbed one and the non thumbed version, and both are excellent. Very lightweight compared to other similar mitts and dry very quickly, which is important for the longevity of the mitt. Hand wash them as you would a cashmere sweater to keep them in top condition and increase lifespan. They come with a mesh drying bag which is a really useful. I think WoWo are still doing 20% discount at the moment, see the thread at the top of this section for the code.
If you're having trouble sleeping you could always read my early review of the mitt, which is still going strong.
http://www.golfgtiforum.co.uk/index.php?topic=270223.0Other than these, Dodo Juice Tribble mitt is very good, or if you like a long haired mitt, then the DJ Wookie's Fist of Yeti mitt, though they do get very heavy when soaked.