Continuous Rotation Servos for Robotics (And what others)??

Hi, Sorry this probably would be better here than in Motors etc....

I have been able to get 4 different servos that are already set up for continuous rotation, direct from the factory in China:
http://arduino-direct.com/sunshop/index.php?l=product_list&c=10
Disclaimer: I would be making some money on these, but not a lot...

Question: What types / sizes of regular positioning servos would be most useful for Arduino and Robotics applications? I am trying to pick 2 or 3 at a good price VS capability. If anyone can suggest a well-known model number I can find an equivalent.

What other motor / motion control things are people looking for???

Thanks!