My personal favorite remains 7-zip. It handles the widest range of formats of any of these utilities: it will compress in 7z, ZIP, GZIP, BZIP2 and TAR formats and extract from RAR, CAB, ISO, ARJ, LZH, CHM, MSI, WIM, Z, CPIO, RPM, DEB and NSIS formatted archives. This range of formats is particularly important when working with Internet applications developed in UNIX or Linux environments such as content management systems or virtual learning platform. It offers excellent performance and has proved to be highly reliable. More detail is available at http://www.brighthub.com/office/home/reviews/10118.aspx.
Judged according to the same criteria as the other utilities, 7-Zip scores best overall: