#4-40 nuts & bolt/screws. Bought a couple boxes of different lenghts from www.boltdepot.com
after cleaning out the local hardware store (not home depot, they don't go that small).
Home Depot does have bags of stick-on cable tie holders tho.
Nylon spacers from www.pololu.com
, bought couple bags of different lengths.
Also crimp housings and terminated wires.http://www.pololu.com/catalog/product/1907
Male terminations for plugging into female headers, female terminations for sliding onto 0.025" square pins.
Have used a lot of both. Bags of 50 wires, very handy.
This place also has lots of those kinds of partshttp://www.phoenixent.com/
also sockets, socket strips, header strips.
Stepdrill/unibit drill very handy for making holes in plastic, does not dig in & rip up the plastic.
I have a couple of different sizes.