Yes, i switched to Firefox! I needed many add-on to get the same level of functionnality as Avant Browser. This last is great, but lack of update and has bug on Vista.
Here is the list of Module I use:
-Tab Mix plus
-User Agent Switcher
-AS Numbers (BGP)
For people using avant browser, here is how to get the same extra functionnality on FireFox:
-URL Alias: Create a Firefox Favorite, and then edit to add keywords. Then you can just type the keyword to convert to the full url.
-Search engine: I went to http://www.searchplugins.net/ to create my custom search:
-mskb: give it a KB number, you directly got the KB page (not a search result)
-eventID: give it an event ID, you get the result page from eventid.net