I know a lot of people use photobucket and all those other sites, but we're starting to see a lot of images being dropped (for misc reasons: not accessed in {x} months, to much bandwidth, etc)
The guy that runs imgur.com is a really cool guy that is offering the service for free. It was set up for digg.com & reddit.com users to post things and not have them disappear due to exceeding bandwidth. It's open to anyone on the net to use for their image uploads. He offers the ability to create an account and manage your photos as well as metrics to who is viewing your images.