It depends. I love printing locally when I need something quick. In Austin I use Precision Camera. When I have more time I'll sometimes used MPIX, CafePress or Shutterfly depending where I find the deals. For printing iPhone pictures I used to love Groovebook (can't beat the deal) but all of the photos got out of hand. For grand wall displays I love WeMontage. So far I've been happy with them all.