If it's just prints, try Walgreens.com with 1 hour local pickup. There are often online discount. Most importantly, you need to start with really great high quality image files. I'm fortunate to have a Walgreen's only 1 mile away.
It depends on what print media and level of quality that you are looking for. Nations Photo Lab, Mpix and Printique are generally considered really good. I've had a few large prints made at Costco which I thought were good quality and priced...
Is there a subforum on this topic I should be posting to and/or searching?
I'm looking for others' experiences in getting their images printed into products appropriate for hanging on their walls and selling.