The one thing I miss from Chrome is the Adblock extension. It has a feature that allows ads on all sites except the ones you explicitly block--a reverse adblock filter, so to speak. I'm ok with seeing ads, but if there's a site I often visit that bothers me (I'm looking at you, weather.com), then I'll block it.

Unfortunately the Firefox version doesn't have this, and neither do the alternative adblock addons I could find.