OSH Park does an outstanding job. I've used them for work and hobby prototyping, and while the turnaround time isn't great (week or two) the quality is first rate.

From what I gather the boards are actually made by Amitron outside Chicago.

Unlike most quickturn PCB fabs they don't bury you with options. The standard options give you everything you need (ENIG, double mask+silk screen, either 2/4 layer, etc.). The OSH Park ordering wizard is a case study in how PCB orders should be done, and for the quality the price can't be beat. Best of all, it's just a "Fred in a shed" operation in Oregon that came out of a hackerspace there.

I used oshpark for a project recently - http://magicsquarefloor.com - the boards were absolutely beautiful.