Code Greene - Just found out about these guys. It looks like they do some great work and rumor has it they do most of their stuff using CakePHP.
Ugly Fruit Media -Brand new start-up out of Provo, Utah. These guys have a lot of experience with front-end development and they do great work
BP3 - Based out of Springville, these guys do some pretty cool sites using Joomla. They are experts at that and can also do Facebook applications and help with advertising and social networking.
Media Rain - My current employer. This place makes the best websites, FLEX, and iPhone apps in the industry. I love them!