The Unarchiver 2.0 RC2

The Unarchiver 2.0 RC2 is such a powerfully designed program for "BOMArchiveHelper.app", the built-in archive unpacker program in Mac OS X. The Unarchiver is designed to handle many more formats than BOMArchiveHelper, and to better fit in with the design of the Finder. It can also handle filenames in foreign character sets, created with non-English versions of other operating systems. I personally find it useful for opening Japanese archives, but it should handle many other languages just as well.
It is very simple to use and install - simply copy it into your Applications folder or whereever you prefer, and then set archive filetypes to open using it. This can either be done the usual way, or by double-clicking the icon to show The Unarchiver's preferences.
If you have a compressed file that The Unarchiver does not open, please post a bug on the bug tracker, and include the file in question, and I will look into whether it is possible to add support for it!

 Enhancements:

• Support for many new formats and algorithms:
• Partial support for SITX archives. Most archives should open fine, but SITX's special JPEG compression is unsupported. (If you are a programmer and want to help out with getting this working, I'd be happy to hear from you!) Some preprocessing filters are also unsupported.
• Other new formats: XAR, ALZip, LZMA-utils, Compact Pro, PackIt, ARJ
• Encrypted RAR archives.
• WinZip-style encrypted Zip files using AES.
• Can decompile NSIS installers to get the files inside. This seems to work for versions all the way back to 1.1o or so, but a lot of guessing is involved so it might fail on some files.
• More compression types in Zip: Deflate64, bzip2, PPMd, LZMA.
• More compression types in DiskDoubler (but still not all).
• Better handling of 7-zip, RAR, LZH, tar and RPM files.
• Extracting files from several emulation formats, such as NDS and ADF.
• Bugfixes and streamlining for the user interface.
• Option for when to create folders for extracted files.
• Option for how to set the date of extracted folders.