Re: Your Favourite Browser Extensions/Add-ons
These are all for chrome. There's probably equivalents for firefox and other browsers.
Google dictionary - allows you to simply highlight a word to get a definition. I don't use it very much, but when I do, it's pretty nice.
Webpage screenshot - Pretty self-explanatory. It lets you take a screenshot of entire webpages, even if they're bigger than your monitor.
Session buddy - allows you to save and manage browsing sessions
Hover zoom - This is probably the most useful one. All you have to do is mouse over a thumbnail or image link and it shows it to you. Makes websites like reddit so much more usable.
Adblock plus - self-explanatory.
YTshowrating - It shows video ratings for the related videos on youtube. Pretty useful if you like to watch random videos sometimes.