I used to love the jungle for giving a lot of wood without needing to reseed it. With the new kinds of woods I find the Borealis wood quite appealing. Although I'm still sad over the fact I need to raid normal forests for making living wood trees.
I don't know about anybody else, but I really love the colour of the regular Oak wood. I prefer other woods painted brown, though, and I think brown Ebonwood has become a favourite of mine, especially for the backgrounds of rooms and buildings. So, Ebonwood.