Firefox users have made some awesome extensions. For instance, take the Paste-and-Go extension; this might seem like a very small and useless extension but in fact it is quite useful. I heavily use this extensions for copying and pasting URLs and I was just thinking, wouldn’t it be useful if this worked for searching functionality also? Well, I did a CTRL+K and typed in "paste and search," guess what was the first link that Google came up with? Paste-and-Go! Basically for paste-and-search you have to press CTRL+SHIFT+S instead of the CTRL+SHIFT+V! Very cool!
I personally think extensions are a very big plus for Firefox and IE really needs similar extensions and for free. One thing that I miss in bare IE is mouse gestures, mouse gestures are such a time saver!