Skitch is a convenient annotation tool for the Mac. If there's an easier way to take a screenshot and add a cartoonish arrow and garish pixelation, I don't want to know. But I don't want to use Evernote as my screenshot platform.
If you were unaware, Skitch makes it pretty easy to use your own host to share screenshots. Just jump into the preferences and setup a new SFTP or FTP connection.
Once that's done, you'll have a new option for sending a screenshot to your own host and getting a URL back on the clipboard.