IZArc is a free and highly comprehensive archiving tool that can open and create all the main archive formats. The current list includes 7-ZIP, A, ACE, ARC, ARJ, B64, BH, BIN, BZ2, BZA, C2D, CDI, CAB, CPIO, DEB, ENC, GCA, GZ, GZA, HA, IMG, ISO, JAR, LHA, LIB, LZH, MBF, MDF, MIM, NRG, PAK, PDI, PK3, RAR, RPM, TAR, TAZ, TBZ, TGZ, TZ, UUE, WAR, XXE, YZ1, Z, ZIP and ZOO.
The program has strong drag and drop support that makes it very easy to use. You're able to drop archives onto IZArc to view them, for instance, or drop files to add them to a new archive. Unusually, you're also able to drop files from IZArc onto other applications: they'll be extracted, then passed to your app, and it'll behave just as though the file or files had been dropped from Explorer.
There's also plenty of advanced features on offer, though. IZArc can repair some broken archives, for instance. A search tool will hunt for a particular file across a group of archives; there's an option to create self-extracting archives; and you're able protect your data with strong encryption.
And the more you use IZArc, the more applications you'll discover for the program. Like the ability to convert between archive formats, for instance (convert a set of img disc images to the more commonly used iso format, perhaps). Or the way IZArc can span huge archives across CDs or DVDs, making it useful as a simple backup tool.
This is the portable version of IZArc.