Google Chrome Extensions
I have started using Google Chrome as my browser-of-choice lately. It has the good performance and standards-support like Safari, but runs both on Mac and Linux, so I have have the same browser experience on both platforms.
It also has some nifty extensions that I like. Here is my current list.
TextAid
This one is really cool. It gives you the ability to edit the contents of a textarea on a web page using the editor of your choice. In my case, that would be Vim, the one true editor.
Because of a limitation in Chrome, you have to have a small external server running somewhere that interacts with the editor, but a link to one is provided on the documentation page for this extension and it is trivial to configure.
Vimium
This one gives you a handfull of Vim-like keyboard bindings in your browser. Very handy and it lets you navigate through your various sites without having to move your hands away from the keyboard. This is a great productivity booster. You can configure it to be disabled on certain pages if there is any conflict with Javascript-enabled custom key-bindings. For example, I have it set to be disabled when I am viewing http://www.google.com/reader/view.
Xmarks
I have been using this great extension for some time now. It is availble not only for Chrome, but also for Safari and Firefox. Keeps your booksmarks nicely synced across all of those browsers.