I am a Kodak Gallery addict. The ease of the website and options make it a clear favorite. Although Shutterfly, Snapfish and Blurb are very close favorites with their different but similar features.
Depending on the photo album, I may prefer to use Shutterfly for their wider variety of layout options. I have yet to use the Blurb company, but their photo books seem much more like a fancy coffee table book or novel than the typical photo album.
A new favorite photo editing website of mine, is Picnik. It's free photography tool that allows you to edit your photos with colors, cropping, lighting, saturation, and exposure. Check it out for yourself!!