WinRAR is a lightweight, flexible, and easy-to-use archiving utility that can unpack most archive formats, as well as compress to both RAR and ZIP. Free to try for 40 days ($29 for single license), WinRAR is definitely top dog in the compression category.
WinRAR's interface is about as simple as it gets. Start creating (or add to) an archive by dragging and dropping your files into the interface or by browsing through the Folder Tree side panel (when enabled). From there, the most common functions are laid out in the form of colorful, mostly intuitive icons, which can all be customized by downloading themes from the company's Web site. Add files to, Extract, Test, Delete, or even Repair archives right from the main interface. Drop-down menus house the program's more advanced features, including self-extracting archives, archive locking, benchmarking, and autodeletion of temp files.
In our performance tests, both creating and unpacking archives was blazingly fast. Compression ratios varied depending on file type, but in general seemed on par with or slightly better than other archiving programs. Overall, WinRAR is a winner because of its speed, simple interface, flexibility with file formats, and powerful advanced features.