I stuck using my dads PC and have been forbidden to download anything so am stuck using IE7 so far I got quite a long list of things I miss about firefox, some may be available on IE7 though.
It automatically checks you spelling anywhere you type
You can duplicate entire tabs and their history
You can undo a closed tab
It restores your session each time and remembers everything, even a half typed reply
Ad-block plus removes pretty much all the adverts on forums
And its completely customizable
https://addons.mozilla.org/en-US/firefox/addon/4327, you can't get better than that