I like www.mpix.com. It's the consumer arm of Miller Labs, which many pro wedding photographers use for printing the products they sell to brides and grooms. They use high-quality papers, offer a few different finishes, and even do photo retouching. They also have print sales and canvas sales a couple times a year that you'll know about if you get on their mailing list.
I wholeheartedly agree with lurkyloo. I use www.mpix.com all the time. I work for a professional photographer and we use Miller's labs for all of our professional photos. I have been very happy with the consumer mpix and use them for my personal photos. It's the same high quality that I've come to expect from Miller's. We purchased our VR photos on disk and I printed them through mpix and was very pleased with the way they turned out!