I can't live without my sidebar in Firefox.If you look along the left side, those are buttons for:
- New Tab
- Bookmarks
- Downloads
- CookieCuller
- Extensions
- Wikipedia
- Add Bookmark
- Open Bookmark Manager
- Firebug
- Find
Install All-in-One and set it up however you like it. Go to Customize Toolbars (right-click the top toolbar, choose Customize), and drag and drop your buttons and dividers and whatever else you want on it.