I participated in the recent Wikinews logo vote and although I was generally happy with the outcome I found the process very messy, borderline and open for improvement.
One way in which voting could be improved on Wikimedia projects would be to integrate a proportional preference voting system like STV right into MediaWiki. See: http://en.wikipedia.org/wiki/Single_transferable_vote
I've had a quick look around and found that there is at least one browser-based STV counting software package out there which is open-source and written in PHP: http://www.demochoice.org/
It would be interesting to see if we could adapt and integrate it into MediaWiki. Does anyone have any technical experience with this software, or know of any other possible options?
Christiaan