Assuming the hubs are usable and the free-hub doesn't need replacement, I would use Velocity Aerohead up front and Aerohead OC in the rear. They are a "best value" in my mind. at $53 and $54 respectively http://www.universalcycles.com/shopp...&category=1712 and http://www.universalcycles.com/shopp...&category=1712

I usually work with Wheelsmith spokes. Double butted will provide the strongest build to hit your goal of durability without being too heavy. http://www.universalcycles.com/shopp...4&category=778
and nipples http://www.universalcycles.com/shopp...8&category=777

That's around $180 in parts and should produce very good wheels but that's not the challenge. Make sure you do a lot of reading and feel confident that you want to learn the skill. Wheel-building is a great skill-set to learn. Just read up and take your time.

Some other Links to reading:
http://www.wellspokenwheels.com/wsw1.htm
http://www.gtgtandems.com/tech/wheandhub.html
http://www.miketechinfo.com/new-tech-wheels-tires.htm
http://www.bikexprt.com/bicycle/tension.htm