3.6 is incompatible with several Add-Ons I use regularly to speed my workflow. I feel so behind the times already.
What add-ons do you use out of curiosity?
Ack! Er, on review some of the ones are not so much "work related" as browsing enhancements I use at work:
Yellowpipe Lynx Viewer Tool
ImgLikeOpera
Right Encoding - this is the only one which is mission-critical, since DevTrack and Firefox were not playing nicely together.
FF3.6 also doesn't like Deepest Sender, a robust LJ client which I enjoy.
Those are the ones which aren't compatible. I'm surprised that so many other ones are, like Rikai-chan and Pera-Pera-kun. Flashblock and NoScript are updated with annoying frequency, so It's not surprising that they're already good to go.