I also made a list for Mozilla Firefox recently.
Feedly – Favorite RSS reader, I just have to have this in every browser I use (come on guys, finish the Android version already :).
AdBlock – No ads, just content.
Google Mail Checker – Shows the number of unread emails and provides a quick access to Gmail. I like how it uses the same tab if you already have one open.
XML Tree – Displays XML documents in a tree and allows executing XPath.
Springpad – Online organizer, notepad, sharing tool, really cool application.
Google Dictionary – Sometimes it just works, but in some pages plainly fails.
Bookmarks – Adds a button for faster bookmarks access.
Awesome Screenshot: Capture & Annotate – The name says it all.
Smooth Gestures – Use mouse gestures to perform common tasks like going back, opening a new tab, opening link in new tab, and so on. This extension has changed to malware! It should be unistalled automatically by Chrome (at least was on my computer).