Here’s an indispensible program for Mac users who work with archives – The Unarchiver. It’s a bit like StuffIt Expander, except it’s open source, faster, supports more formats and doesn’t require you to
sign your life away to the developers. In fact, you could get rid of StuffIt altogether, but The Unarchiver doesn’t support the propietary .sitx format which is (very) occasionally used by people, so you’ll still need it for that.
It also beats OS X’s built-in zip support by allowing you to have it open the folder automatically after the files have been extracted. All in all it’s a good little application, found through.