If you are using Firefox 2.0 or early version, i have found some good add-ons for your Firefox. This Add-ons will make your Firefox more easier to use.
This add-ons Toolbar in your Firefox and display related web site which have same content with web site that you open. For example if you open www.youtube.com this add-ons will display web site like Google Video, Daily Motion, and other related web site.
Help you to download video from YouTube, Google Video, and other web site that provide video streaming. To download video, just visit Google Video and click VideoDownloader icon in the Firefox Status Bar then you will get Download Link to download Video. You can see the demo here.
3. Session Fix
Save session will only work when your Firefox close unproperly, but with this add-ons you will be ask to save your session or not.
4. File Title
If you save Web Pages in Firefox the file name will be index.htm, search.htm, which not user friendly. With this add-ons the file name will be like in IE, which use web title in file name.
With this add-ons you will be able to download any media in any web pages. You can also preview the media before you download it.
This is a coolest Firefox add-ons, you will be able to preview from a link.
Browsing faster with with this add-ons. This add-on will optimize your Internet connection to improve your browsing speed.
This add-ons will add new menu in Fierefox Menu Bar. From here you can access all Google Ulitilites like Adsense, Gmail, Earth, and other Google Utilities.
This add-ons will gives you quick access to Google’s Advanced Operators directly from the context men.
That’s all plugin that maybe usefull for you.