Golden Motor - Magic Pie II
It boasts a 20 Amp controller that is built into the hub motor itself. This thing regularly overheats on me at about the 5 - 8 mile range, if it's above 60 degrees outside.
I'm building a second bike specifically for reliability. This time I'm running a Crystalyte 5303 with a 35 amp controller. Should be a lot more reliable, though more expensive.