I've installed extensions to un-shorten Twitter links and make Google search results link to pages directly, but they break on a regular basis.

For tabs I use Tree Style Tabs, and a little UI tweak I like is Reload in Address Bar. I also removed all of the space around the address bar because it gives me more space to work with when editing URLs.

I use Pinboard, and the Pinboard+ extension is very unobtrusive. In fact I usually forget to use it :(