I really like Snapfish for photo prints and products. It is easy to use and the quality is great. Prices can be a bit high, but that's my only complaint.
I LOVE Canvas on Demand! At first, I ordered the 16x20 sizes I purchased through Groupon. After seeing the high quality, however, I now frequently order the larger sizes. These make fabulous gifts, too!
The site is awesome! I have purchased at least 50 Groupons for a variety of items. Every one resulted in big savings and the product quality of participants has been awesome! I have recommended them to all of my friends.