Internet 2: Browsing

Opera (free)
http://www.opera.com/products/desktop/

Safari
http://www.apple.com/de/safari/download/

Google Chrome
http://www.google.com/chrome

Mozilla Firefox (os)
http://www.mozilla.com/

Extensions for Firefox:
adblock plus (free)
http://adblockplus.org/

ietab (free)
http://ietab.mozdev.org

download manager tweak (quite old)

down them all (free)
http://www.downthemall.net/

GMarks (free)
https://addons.mozilla.org/de/firefox/addon/2888

Google Notebook (free)
http://www.google.com/tools/firefox/index.html