Easily block Flash animations in Firefox with Flashblock. Has a whitelist so you can let your favourite sites through. I’m finding it handy to stop advert-laden (mostly MSM) sites stealing inordinate amounts of CPU just to show their ads. (Though the Herald-Sun must use something else for its slow moving mid-page picture banner thingy.)
Could Democracy be the Firefox of media players? It looks pretty cool, and there’s a new version just out, though at the moment I’m using the Real and Quicktime alternatives from Free-codecs.com.
Looking for something like Co-pilot, but free? How about UltraVNC Single Click? (via Anthony)