Another similar vote.
I primarily use 7-Zip. It handles standard zip files as well as anything when I need to distribute something. It extracts RAR for when I download something. And for my own personal use, I'll use .7z as the format. On the rare occasions that I need to create a RAR, of course I need to use WinRAR.
Do we have enough critical mass, at least in this community, so that 7z is a viable standard? It does have a number of advantages over zip.