The 7-Zip format compresses quite better than standard Zip. I only mention this to avoid confusion. The 7-Zip files are those ending in *.7z, not *.zip. However, 7-Zip does regular Zip and also does RAR as well as decent bunch of other formats.
As a side tip, if you want to compress something using the 7-Zip format, you can choose to create an *.exe instead of *.7z for those friends who don't have or don't want to install 7-Zip. 7-Zip is also available for Linux.