Snagit is worth a look: http://www.techsmith.com/snagit-mac-features.html

It doesn't support Dropbox and it's not quite as good on the whole as Skitch was, but it's the closest thing I've found (and it does video capture too).

If you don't need the annotation tools and just want to get a screenshot online fast, Droplr is the best I've found: https://droplr.com/hello