I just recently dicovered 'PowerArchiver'. Its used to compress and decompress various file formats such as ZIP, RAR, JAR, CAB etc. Zip and RAR being the most common for me.
Before, I had winzip and winRAR running now I just have POwerARchiver which opens almost every file format there is. It makes my right-click menu tidier and shorter.
Winamp3 is great Musicplayer, I find it much nicer to use than Windows player.
RegVac is a really easy to use System optimizer. It cleans the registry and system of unused files left behind from unistalls etc. Much better than JV-16 powertools which I used before.
WS_FTP pro, I really good FTP client. I use it to upload website files to my webspace. Its very easy to use.