My Top Ten Favorite Thunderbird Extensions... so far

I got the idea to do my own favorite Thunderbird extensions list from the blog TwisterMC.

I think that if more people listed their favorites some of the "hidden gems" would get more exposure and perhaps encourage the developers to continue their great work.

So here is the list:

1. Lightning - This allows calendars in Thunderbird. I was using Sunbird and I liked it but this is a lot better for me. It has allowed me to actually move forward on getting my GTD system setup. See my previous post.
2. Provider for Google Calendar - This allows the two-way (not read only) access to your Google Calendar within ThunderBird. See my previous post.
3. Minimize to Tray and Minimize to Tray Enhancer - This allows me to minimize Thunderbird to my system tray, which cuts down on the cluttered feel Windows gets when many apps are open.
4. QuickText - I have just started using this and it is already saving me time. I have a regular signature that I use on some but not all emails. This allows me to insert commonly used text into my email so I can easily add that signature when I need.
   
5. Thunderbrowse - This allows web links to be viewed within Thunderbird, which I find to be useful from time to time.

Let me know what extensions you have found to be useful!