After going through the HiTec HS-81 and 85 servos as well as most other 'name brand' micro/mini servos and having them strip, refuse to center or quit altogether, I settled on the Tower Hobbies TS-35 Hi Power mini servo.
http://www2.towerhobbies.com/cgi-bin...?&I=LXPB46&P=7
Replacement gears are only $2.65 a set, but I've only had to replace 4 sets of gears over the last 3 years.
D