I've successfully used BatchPCB.com, dorkbotpdx.org, and goldphoenixpcb.biz. All delivered a good product.
For a small number of boards (e.g. 3), I prefer dorkbotpdx. Laen is really good to work with, the boards are well made, and the turnaround is usually pretty quick.
For a larger number of boards (155 sq inches), I normally use goldphoenixpcb. Their turnaround time is pretty good, too. And the boards have been of good quality so far. There are some price add-ons for lead-free, extra routing points, etc. But all in all still a good value.
BatchPCB is a little pricey and way too slow for my current tastes. But the boards I got from them never had any problems. If you are not in a hurry, they are also a good choice.
I'm waiting on a couple of small orders from iteadstudio. Assuming that goes well, I'd probably add them to my list of options.
Jim