There is one area of browser extension that people are very much unsure about and that is Passwords. People in general tend to create terrible passwords, too easy to guess, too easy to forget, so you get Password services like LastPass. I haven't really used any of the other password services before because I was uncomfortable with the idea. However, as my world got more and more connected, I have found it more and more attractive as an option. Currently my browser of Preference is Google Chrome. I like it because it is fast, and bleeding edge, the two things I like in a browser. It also doesn't hurt that it is by Google (and the Chromium open source dev team) so that certainly doesn't Hurt.
Extensions on Chrome however are somewhat of a mixed bag. The SDK does not allow you to do alot of the things you can do in firefox which is why we have yet to see awesome firefox extensions or their equivalents of DownThemAll, Stumbleupon (there is an addon, but it uses a DHTML bar, not exactly the same thing) etc.
LastPass however is almost entirely based on their own secure servers. You can almost get all the functionality that would be necessary out of a Bookmarklet which is quite amazing. Normally I would shy against storing all of my personal data on a remote server, but if Google Trusts LastPass enough to make them a featured addon, and I beleive Martin Brinkman at Ghacks also uses the service, then it must be pretty good.
The options that you have on how you want things autocompleted, form filled, and remembered are quite amazing really. I recommend Lastpass to everyone. Chrome or not.