This is not just an archive manager actually but is also a file manager as well. But since Windows Explorer is pretty darn good, PeaZip won't be able to impress much here. But it lets you securely delete, encrypt or split your files as easy as just right clicking on them!.
*. Can handle all the OpenSource fire archive formats such as:
7z,7z-SFX, FreeArc's ARC/WRC, bzip2: bz2, tar.bz2, tbz, tb2, gzip: gz, tar.gz, tgz, PAQ8F/JD/L/O, LPAQ, ZPAQ, QUAD/BALZ, tar and WinRar and WinZip formats. Interestingly PeaZip has a file archive format of its own called "PEA" with all the modern features.
|More than an archive manager...|
*. Add passwords.
*. Hash check.
*. Create self extracting archives.
*. Has a portable version thus you can just put it into your USB drive or HDD and take it anywhere (it won't touch the Registry of the OS while running which is a standard feature for portable apps, I think).
*. Run MS Windows built in system tools directly from its file explorer, such as: Disk Defrag, Disk cleanup, System benchmark, task manager, etc.
*. Create "keyfiles" using random secure algorithms.
*. Open Command-prompt inside any folder (while using PeaZip as the file manager).
*. Integrate its feature into the "Sent To" sub-menu are just a few to mention.
As said before, as a file manager, it's not as impressive as the default one in the Windows but as an archive manager, it is super excellent! ;-). It has few built in themes (one in particular for the Win 7 users too).
So, if you're looking for an archive manager that can deals with almost all the popular archive (including e-mail handling) formats and few additional ones such as securely deleting files/folders and want all those features in a singe application which should also be free and opensource (oh cooome on! :P), then PeaZip is the one to go for without a doubt. Get it from this PeaZip Home page.