Industry Nine Hydra hubs
been running hydra's for almost a year with some sixth element rims, i'm liking them a lot. hardly any drag, nice and loud and the near instant engagement is great on really technical climbing.
reguarding the pedal comments above, if your used to being clipped in on the road, you'll be fine offroad as well. i can have a dab as quick as i could if i was on flats, the only time its caught me out was when i stalled trying to get over a big lump of rock and unclipped the wrong foot, was very amussing for my mates as i disaperard into a load of bracken. i do use pedals with a decent big platform(crankbrothers mallet e), if your slipping and sliding down a rough rooty section and need a dab at least theres good support if don't get clipped straight back in.