I've used Explorer for years, but I'm slowing migrating to Firefox. It's user friendly, opening tabs for multiple sites rather than launching new sessions.
1. Download Firefox @
http://www.mozilla.com/en-US/firefox/
2. Check out available add ons @
https://addons.mozilla.org/en-US/firefox/
Here are a few to consider
Firebug @
https://addons.mozilla.org/en-US/firefox/addon/1843
You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page.
Greasemonkey @
https://addons.mozilla.org/en-US/firefox/addon/748
Allows you to customize the way a webpage displays using small bits of JavaScript. ...
Fireshot @
https://addons.mozilla.org/en-US/firefox/addon/5648
This plugin provides a set of editing and annotation tools, which let users quickly modify captures and insert text and graphical annotations.
Delicious @
https://addons.mozilla.org/en-US/firefox/addon/3615
Integrates your del.icio.us bookmarks and tags with Firefox and keeps them in sync for easy, convenient access.
Clipmarks @
https://addons.mozilla.org/en-US/firefox/addon/1407
Your clips are saved on clipmarks.com and can easily be syndicated to FriendFeed, Twitter, Facebook or saved to your blog.