The Archive Browser is a program that lets you browse the contents of archives, as well as extract them. It will let you open files from inside archives, and lets you preview them using Quick Look.
It is based on The Unarchiver, which means it can handle a large number of different archive formats: It can handle common formats like Zip, RAR, 7-zip, Tar, Gzip and Bzip2, as well as older formats like StuffIt, DiskDoubler, LZH, ARJ and ARC. It can also handle other kinds of formats, like CD and DVD images such as ISO, BIN, MDF, NRG and CDI, many Windows self-extracting EXE files, and can even extract media from Flash SWF files and images from PDF files. See the supported formats page for a full list.
It will also handle different filename encodings gracefully, and for the curious, it will show a lot of information about the archives and their contents.
(Note that the App Store version is sandboxed, while the non-App Store trial and full versions are not sandboxed. If you prefer the safety of the OS X sandbox, you should get the App Store version. However, the sandboxed version needs to ask you for permission for certain operations, and if you find this annoying, you should get the non-App Store version.)
If you have any trouble with The Archive Browser, please file a bug on the bug tracker, or post a question in the support thread.
More screenshots here.