Sort:  

If you want your prints to look their best try MPIX. As a professional, this is where I get the majority of my work printed.

https://www.mpix.com/products/prints

For getting your photos put into book form I recommend Blurb. Prices are decent and the quality is plenty good for most people.

http://www.blurb.com/

If you want your photos printed quick and nasty, just send them to your local CVS or Walmart and have them do it. It is just nice to hold a photo in your hand no matter where you get them printed.

Happy printing!