Grad school and The Girl cut into my funding, and I've recently accumulated $200 in book returns on Amazon. I wanna build up a set of wheels to replace my stock ones on my Gary Fisher Cobia (with SuperCal Fox 32 fork

Gonna Use stan's 29'er rims, and DT Revo spokes (or CX rays if I can afford them later.)
For front and rear hubs, what are my best options when looking for a set with this criteria?:
* 135mm
* Disc (preferably 6 bolt)
* 9mm QR Traditional Axle
*** DURABLE FREEHUB
*** No more than $250-300 for both hubs
- I would like to stay with a silver/light/white option, but not 100% necessary.
I have to flush or replace the freehub on my Shimano M475 alloy hubs like every six months... I'm a knowledgeable roadie, but I don't know a whole lot about MTB componentry yet, so not sure whether this is just because they're low end hubs or if West Virginia mud is farking them up quickly?
I haven't bought rims yet, so number of spoke holes isn't too important yet. My LBS said he built up a pair of HOPE hubs recently, and really really liked their quality, serviceability, and the capability of changing the axle size.
Whadd'ya say guys? I know how to WW things up, but it's tough with limits. What would you suggest, and what should I look for when getting hubs?