7-Zip is a free, opensource zip/unzip program. I've tried a lot of zip/unzip software and for some reason I keep
turning back to 7-Zip. Usually it's because of infuriating bugs in the other software, lack of updates, or
whatever - the bottom line is 7-Zip is simple, reliable and continuously updated. Although it lacks some zip
formats, more formats are being added all the time.
Integration into Windows Explorer is convenient, allowing
zips/unzips to be performed through easy right-mouse-clicks.
Packing / unpacking: 7z, ZIP, GZIP, BZIP2 and TAR
Unpacking only: ARJ, CAB, CHM, CPIO, DEB, DMG, HFS, ISO, LZH, LZMA, MSI, NSIS, RAR, RPM, UDF, WIM, XAR and Z
I recommend this to any home user looking for good, dependable compression software.