I used the SY85STH146-4208 motors for my machine - they're very torquey. You will definitely need the high voltage drivers. Irving did an excellent tutorial on choosing motors:

http://www.mycncuk.com/forums/showth...eed-A-tutorial

When I got mine, it was a case of "as much as I could afford" (after having a brief discussion with Gary about it).

I also got the previous generation for the driver than the one Zapp's currently offering in their NMEA-34 Kit 2.