I just wanted to let everyone know about
Photo Rental Source. They're a lens/body/flash rental company based out of Houston. I had my first paid shoot last week, and needed to rent a Canon 24-70 f2.8. I was going to use one of the other rental companies that everyone is familiar with, but happened to run across these guys doing a Google search. The best part about it is that if you're in their vicinity in Houston, they can meet you somewhere to deliver the lens, and you can drop it off at a Postnet facility on Bissonnet (2726 Bissonnet Street) when you're done (they don't have a storefront). This will save you about $25.00 in shipping. If you don't live in Houston, or are out of their meetup range, they work just like the other rental places and will ship it to you.
I highly recommend them to anyone in need of equipment rental. Communication via email was excellent when arranging a place to meet. They're also a TPF member (PRS Photo).