Here's my ridiculous list of extensions: Adblock Plus, Better Gmail 2, Chromifox, Download Statusbar, Edit Middle, Exit Button Firefox, Extended Statusbar, FireFTP, Fission, Hide Menubar, IE Tab, Locationbar2, LogMeIn, NoScript, Prism, Stop-or-Reload Button, Stylish, and Tabs Open Relative. I have a few things setup to make it mimic the Chrome interface (which I love): Colors via Chromifox, tabs on tab via Stylish, and a small script I wrote to hide the titlebar completely (hence the Exit Button addon). Here's a quick picture of the top of my browser; other than that, there are no other toolbars (and no bottom statusbar).
I love minimalistic designs.