A pneumatic system is defiantly the way to go, one piece of advice that is relevant for most mechanical sub-assemblies, is try to reduce the amount of work an actuator has to do. This is especially relevant for heavier loads (i.e. 10 lbs). Use latex tubing, springs (make sure you wire them!) and gas springs to help reduce the experienced weight on an actuator, and torque/power required. Not only will this technique cut down on wear and tear, but it adds some level of finer control. Just be careful with large preloads!
