I've been using Google Chrome as my main browser pretty much since it came out. I love the minimal interface, bookmark sync, searching from the Omnibox, and the start page. Somewhat recently Chrome decided to jump on the extensions bandwagon, and I think it's great. Here is a quick list of the Chrome Extensions I use:

• LastPass - This is my choice of password manager. It doesn't do everything perfectly, but I love that it's always synced across all my computers and browsers.
• ProxySwitchy - I've talked about this one in a couple other posts, but this is the quickest way to switch between using a proxy and using a direct connection to the Internet. If you want a tutorial for how I use it, click here for Mac or here for PC.
• Concentrate - I use this one when I need to get down to work and avoid the temptation of the Internet. It allows you to put in any number of URLs, then set a timer for how long you want to be blocked off from them. It's not perfect, but it's the best I could find for my purposes. I like it because I can set it to "Concentrate" mode when I want to, and for the length of time I want. Others like Chrome Nanny have similar behaviors, but operate on a set schedule, which is not optimal for me. As a side note, if you try to block Google Reader (http://www.google.com/reader), it will also block Google.com. Rumor has it they're working on getting more sophisticated blocking, but for now it seems to work just by the domain.
• Google Voice - I don't use Google Voice on my phone, but I use it for voicemail and texting. This extension allows me to text from within the browser plugin window. It also grabs your Google contacts, so texting or calling any of those people is a piece of cake.
• AdBlock - I didn't get this one to block ads. I use it primarily to hide the "Explore" section from Google Reader. That was an endless time wasting pit of distraction, so I used Adblock and this quick tutorial.
• RSS Subscription Extension - This one I leave on all the time, but rarely use. I hated that there was no easy way to subscribe to a site's RSS feed in Chrome. With this extension, an RSS icon appears in the address bar when a feed is found for a site. Just click that icon to subscribe (I use Google Reader, so I don't know about how it works with other readers)

Anyway, that's what I use. What other extensions have you found helpful?