This is Jeremy Morton's theme for Firefox, updated to support various additions (Dev tools, new tab page, etc)
all credit for the original theme goes to: Jeremy Morton
Original "Firefox 3 theme for Firefox 4+":https://addons.mozilla.org/en-US/firefox/addon/firefox-3-theme-for-firefox/
Jeremy Morton's profile: https://addons.mozilla.org/en-US/firefox/user/jeremy-morton/
how to get tabs on bottom:
1. go to about:config
2. search 'browser.tabs.onTop' or 'onTop' (without the quotes)
3. double click 'browser.tabs.onTop' (without quotes) to set it to false
that's it! no restart, just simply tabs on bottom!
how to get menu bar:
1. right click empty space on any toolbar
2. click menu bar
there! now you should have the (near) full classic experience!
to get non-reviewed or earlier versions (if there are any) go to: https://addons.mozilla.org/en-US/firefox/addon/firefox-3-theme-for-firefox-1/versions/
recommended if you want full classic look:
old default image style: https://addons.mozilla.org/en-us/firefox/addon/old-default-image-style/
Classicish Addons Manager: https://addons.mozilla.org/en-us/firefox/addon/classicish-addon-manager/
Classic Toolbar Buttons (for old download dialogue, configure every setting off or default, then check 'classic downloads window'): https://addons.mozilla.org/en-US/firefox/addon/cstbb/
RSS Icon in awesomebar: https://addons.mozilla.org/en-us/firefox/addon/rss-icon-in-awesombar/
fix the back-forward dropmarker's (if installed) style to look like in Firefox 3: http://userstyles.org/styles/89830/firefox-3-theme-for-firefox-4-dropmarker-fix?r=1372552167
--------- the original, unedited description ---------------
As some people think the default Firefox 4 theme is too 'washed out', this theme brings back the colorful look of the default Firefox 3 theme, in Firefox 4 (or later)! This theme is based around the Windows ('winstripe') version of the Firefox 3 theme, as seen outside of Windows Vista/7's 'Aero' mode.
If you'd prefer the Firefox 3 theme as it appears under Windows Vista/7's 'Aero' mode, check out my Aero version of this theme, at:https://addons.mozilla.org/en-US/firefox/addon/firefox-3-aero-theme-for-fi/
Or for those who prefer the Firefox 2 look:https://addons.mozilla.org/en-US/firefox/addon/firefox-2-theme-for-firefox/