If you have a big "bunch" of tower credit and really want a servo to match that level of radio:
http://www3.towerhobbies.com/cgi-bin...?&P=9&I=LXENCF
If you want to spend a little less:
http://www3.towerhobbies.com/cgi-bin...&I=LXTCX9&P=ML or
http://www3.towerhobbies.com/cgi-bin...?&I=LXFCBD&P=7 or a little less still:
http://www3.towerhobbies.com/cgi-bin...?&I=LXCLRW&P=7
I'm not really confident/sure enough in what Tower sells in terms of anything cheaper than those to give a cheaper recommendation.