I use WinZip to open most zip files. But it does not work with Linux compressed files like tar, gz and tgz. For those, I have been using WinRAR. However, I am not a big fan of WinRAR and above that, it only comes with a 40 day trial version. So, I was searching for an open source replacement. It appears that 7-Zip is a great file compression software. I just tested and it works great with gz and tgz files.
Download 7-Zip 4.65: http://download.cnet.com/7-Zip/3000-2250_4-10045185.html
Official website: www.7-zip.org/