I currently use Foxy tunes which is pretty good... allows me to control any of my media players (winamp, wmp, fubar2000 etc) from my firefox browser! All controls show on bottom of page (on toolbar)
http://www.extensionsmirror.nl/index.ph ... dia+player
I also have Fireftp which is a small ftp client - great for me uploading small files (without having to go into my ftp applications, makes like alot quicker
http://www.extensionsmirror.nl/index.ph ... hl=fireftp
I also use Download manager tweak - gives some advanced features - pretty handy
http://www.extensionsmirror.nl/index.ph ... ad+manager