The ReadWriteWeb blog bemoans the lack of browser extension support in Google Chrome (so far), and offers a list of handy bookmarklets that can tide you over for now.
From Gmail This, to Dictionary, to Delicious 'marklets, this collection looks a lot like our top 10 useful bookmarklets. Of course, bookmarklets don't take up the memory or require installation like add-ons do, so these are worth dragging to your Firefox toolbar as well.
Make "Add-ons" for Google Chrome Using Bookmarklets [ReadWriteWeb]