Shameless plug: If you have access to a 3d printer, I've made a minimalist mount for the LifeCam-3000 here:
http://www.thingiverse.com/thing:1494829
The Microsoft LifeCam HD‑3000 is one of the most common due to its small size and low price, as well as being available from FIRSTChoice for several years.
Axis network cameras are also popular due to their many features and adjustable options.