Same here, deleted a bunch of my bookmarks but like someone said, Firefox keeps a 5 day rolling backup of your bookmarks.
http://kb.mozillazine.org/Lost_bookmarks
The import bookmarks from file feature of the Bookmarks Manager will add the contents of any bookmarks file in HTML format to your current bookmarks. You can import a bookmark backup file to restore missing bookmarks from within your Mozilla browser as follows:
* Mozilla Suite/SeaMonkey: "Bookmarks -> Manage Bookmarks... -> Tools -> Import..."
* Firefox 2.x and earlier: "Bookmarks -> Organize (or Manage) Bookmarks... -> File -> Import... -> from File"
* Firefox 3: "Bookmarks -> Organize Bookmarks -> Import and Backup -> Import HTML... -> from an HTML File"
When the file picker appears, navigate to the folder that contains the bookmarks file you wish to use and select that file. Windows 2000/XP/Vista users can navigate to the Firefox profile folder by typing "%APPDATA%" in the file field and pressing Enter, going into Mozilla, then Firefox, then Profiles, then xxxxxxxx.default (where xxxxxxx is any sequence of numbers and characters) then go into the bookmarkbackups folder and select the bookmarks-(date).html file you wish to import [4].
Note: In Firefox 3, you can use the "Import and Backup ->Restore" feature in the Bookmarks menu (see below) to replace your current bookmarks with a dated backup file.
Quote from gaj:
WARNING!!!!!
firefox deleted a bunch of my bookmarks.
fortunately, i saved them first.
i never d/l'ed things (previously) early on, and will go back to being cautious in the future.
it appears faster...but the "awesome bar" sucks, and i've already disabled it.