The Hitec D645's at $39,95 are a nice sport servo. Newer technology and HV compatible, with about 180oz at 7.4v's, about 160oz at 6.0v's. They also have the 5645 version, which are digitals, with a little less torque, about $5.00 less then the D-series, and the older analog 645's at about $29... All have been decent workhorse servos, and Hitec has great service if anything ever needs work done or service on them. Very fast if you're in Cali, as they're down in SanDiego area now.

I'd vote for the Hitec D645's myself for that sport/scale flyer. There are other brands as well, but I've been using Hitecs with good results for a long time now, and they're easy to get, from any mainstream supplier.