i mainly use straight needles and i prefer wood. they are always relatively warm to the touch unlike metal needles that can get quite hot or cold. i've been taking very warm, lengthy showers this winter and the humidity actually condenses on my metal needles. o_O
i also like wood because they're so natural. i feel very zen-like when i use them with natural fibers. plus, they look great.
i would agree with the speed thing though. when knitting in the round wood is NOT your friend. my yarn constantly gets stuck at the join and the texture of the wood needles makes it quite challenging to push the loops past it. i need to replace my wood circulars with addi turbos.