Rated 5 out of 5 stars
Bookmarklets: SiteLauncher by David Morrison is the first addon that allows me to launch any bookmarklet with a shortcut :-)
Possible improvement: I understand the author pre-fill some web sites that won't fit with all users world wide. Now, allowing 2 keys (e.g. Alt+Maj+XY) would double the power of SiteLauncher.