I was happy to see this hint about Quick Look support for examining the contents of zip files. However, since I do a lot of my work back and forth with *nix users, most of my compressed archives are gzipped or bzipped tarballs.

I was directed to the free BetterZip Quick Look Generator. This Quick Look Generator will examine the contents of ZIP, TAR, GZip, BZip2, ARJ, LZH, ISO, CHM, CAB, CPIO, RAR, 7-Zip, DEB, RPM, StuffIt's SIT, DiskDoubler, BinHex, and MacBinary files. And as noted, it's free!

[robg adds: While this is mentioned in the comments to the referenced hint, given that this plug-in really handles most types of compressed files, I felt it was a unique enough Quick Look plug-in to merit a hint of its own. This plug-in is apparently based on features in macitbetter's $19.95 BetterZip, which allows you to extract single files from archives, search within archives, create them via drag and drop, and much more -- I'd not heard of it before, but it's now on my Pick of the Week to-be-looked-at list (and yes, PotW will return, once the rush of Leopard hints slows down a bit!).]