My top five favorite Firefox extensions

My browser of choice is Firefox, and to make Firefox even more efficient, I've plugged in a few Firefox extensions that do specific tasks. Here are the five Firefox extensions that I use every day:

• Foxmarks is a free add-on for your Firefox browser that syncs your bookmarks across multiple computers. Basically, this means that my bookmarks can be accessed from anywhere, and they're backed up every time I shut down my computer.
• AideRSS Google Reader Extension: I use both Bloglines and Google Reader to keep track of all my RSS feeds. The AideRSS Google Reader Firefox extension helps me find the best content within my feeds instantly via a simple scoring system.
• Diigo Web Highlighter and Sticky Notes: I use this one all the time to leave sticky notes to myself on Web pages, whether that be an idea I want to follow up on, research, or just commentary.
• Session Manager has saved my bacon quite a few times. It saves and restores the state of all open windows - either when you choose to restore them, or automatically at start up and after crashes (which unfortunately, happens to me quite a bit).
• Download Statusbar: This extension is quite simple; it displays your downloads in a tidy status bar at the bottom of your browser, rather than a large pop-up window right in the middle of what you're doing.

See how useful these are? What are your favorite Firefox extensions?