[*] URL Shortener, shortens the current page to goo.gl, and provides a QR code. Handy.
[*] Google Reader Notifier, links to Google Reader, and provides a handy toast notification on new unread feeds.
[*] Google Dictionary
[*] The Unofficial RuneScape Toolbar for Chrome Extension, does what the Toolbar for Firefox/IE does, except in Chrome. And provides a bit more functionality too.
[*] Gmail Checker, snapshot of the inbox, straight from the extension, with toast notification.
[*] DeskSMS, all SMS gets pushed to either GTalk, Gmail, this browser extension, or its web interface. I can reply to it from here instead of reaching HALF AN ARM'S LENGTH to reply from my phone #firstworldproblems, it also allows me to annoy my friends with 90wpm texts in quick succession

[*] Chrome to Phone, pushes the current webpage to your phone, useful for when reading some long, interesting article, and have to go somewhere.
If an extension allows me to get more things done in less work, it'll be installed. That includes typing in mail.google.com (UGH), or reader.google.com (UGH), or runescape.com (UGH UGH UGH), goo.gl (I can never get it right, it's usually goog.gl or some crazy variation, and then afterward having to paste the shortened URL and adding .qr at the end, **** it), or having to e-mail or SMS myself the link I'm currently at. TOO MUCH WORK THERE. My Most Visited pages (Speed Dial), I visit once a day, but since there's only 8 of them, I forget to check other important things. These extensions also help me remind myself that there are other important sites to check, like Reader, Gmail, and the RS news.
If I HAD to remove some extensions, it would probably be replaced by an app on my phone, which would add on to more things to check once I'm on it. It'd be Gmail (thank goodness for push e-mail and push e-mail scheduling), DeskSMS (it's really a half arm's length away, bless it), and the RS toolbar (I'd already purchased an app that can do more things than the Chrome version can, what the hell).