Lawson Kurtz outlines some requirements and conclusions for a series of screenshot apps for the Mac. Check the comments for apps that were missed. I never realized Monosnap supported so many platforms, but it looks good too.1 Certainly Droplr should be on the list.
I think that the one additional requirement I'd throw on the list is access from mobile (like iOS) that works for upload and browsing.
I never really liked the iOS app and sync requires an account with their service. ↩