We've been experimenting with voting systems in order to decide where to eat. We weren't sure which system was the fairest, so we built apps that used plurality, probabilistic, instant-runoff, and preferential voting. It reached the point where we were voting on which voting system to use!
The system we settled on was a modified Borda count (http://en.wikipedia.org/wiki/Borda_count#Modified_Borda_coun...). Our app isn't public, but I recommend this system, because it seems to have maximized happiness in our company!