My main browser is Firefox 3.6.3 (and Thunderbird), but also testing out Seamonkey (Mozilla), and Opera.
If you're using Firefox and like to test betas, here's directory of OS options for 3.7 - oddly I found this while searching for "MineField" which I believe was an older trimmed down Mozilla browser.
http://ftp.mozilla.org/pub/mozilla.o.../latest-trunk/
unbeknownst to the casual internet user, there are tons of options depending on your preferences, OS, and security.
http://www.webdevelopersnotes.com/de...sers_list.php3