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.
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!