If you work with zip (compressed) files as much as I do, you will find that the installed compression utility in Windows Vista is very slow.

My recommendation is to install 7-zip, a free, open source program.  This is great for Windows XP as well.  If you open the pop-up menu (right-mouse click) for any item you will find a new 7-zip menu that gives you several easy options for compressing and uncompressing files.

It also handles several other compressions such as Unix gzip and tar format.