I have 7-Zip installed, and it hasn't changed the default file associations. I've changed the associations for .rar and .7z, but I can't find a way to change .zip.
I looked in Default Programs\Set Associations, and I searched for .zip, but it's not there. Seriously it goes from .z, .z96, .zoo. It seems to skip .zip. How can I fix this? If it needs to be, I'm fine with registry edits.