We run the E-flite 370/4100kv, with 8 tooth pinion and another one with an 11 tooth pinion. Kyle prefers the performance of the 11 tooth but the battery takes a beating. Although the 8 tooth is OK, I think we will settle on the 10 tooth.
We run the E-flite 20 amp esc for main, and a gws ICS50 2 amp esc and G90 gyro for the direct drive tail setup.

Here is a video of the 8 tooth
http://www.raymondstacy.com/pics/bladecp172007.wmv

Here is the 11 tooth
http://www.raymondstacy.com/pics/kbcpp.wmv