I am a massive fan of Chrome, and have had it as my default browser for months at the expense of Firefox. Extensions have been available for a while and once downloaded the icons sit neatly alongside the address bar in the top right of the browser.
There are not as many available as in Firefox, as you might expect, but I already have Facebook, Delicious, Dropbox, Gmail, Digg, Evernote and Chromed Bird (an impressive Twitter extension).
Google has released a promo video for Extensions this week and it is equally impressive.
At the same time as this, a promo was released for Google Translate. I have only started using this a lot recently since an old French friend got in touch via Twitter. In my limited experience it seems to be a great product, and again, the video is fantastic.