I’m looking to get a set of motors for a new Prusa Mendel. How many N*cm should I be looking for? And does anyone have any experience with 200 vs. 400 steps/rev? I want to get the best print quality possible.
Thanks for the feedback.
The drivers I’ve worked with all have microstepping, so to some extent steps/rev doesn’t matter a lot: you can get finer steps by microstepping than the printer can print.
This page suggests 13.7 Ncm, and I would consider it a good minimum in most cases (not including extruders): http://reprap.org/wiki/Stepper_motor#Holding_Torque
Also pay attention to the other specs. You want a motor with a voltage rating in the 2.4-4V range for the 12V supply.
400 steps/rev will get you higher quality, but it will double your step rate, and depending on the rest of your electrical and mechanical setup, it may limit your top speed due to the maximum step rate achievable by the 16mhz microcontroller.
These or similar are the best motors Ive ever used:
I second @Brian_Evans suggestion. The Kysan motors have been nothing but a dream for me. While everyone else struggles with speed and torque, I’m just whistling away.
Good specs on that one, though personally I’d like to see a bit less phase resistance.
I prefer this 400-step model: https://www.sparkfun.com/products/10846
It has a tiny bit less torque, but twice the resolution and it can maintain full torque at higher speeds.
I own that one for my delta, @Whosa_whatsis . I haven’t had the chance to really put it through its paces though. 
Thanks for the feedback. Will the choice of 200 vs. 400 limit the driver electronics choices if I don’t want to give up speed? And I don’t know anything about which drivers support microstepping.
Any driver you would want to use will be based on the A498x series or the DRV882x series of chips, and will work with either motor.