I've seen a few of these sort of posts around lately, and because I
can't think of anything original to blog about disagree with them all, I am going to list my own top 5 extensions you absolutely must have. Because I said so.
I know, I know. It "robs innocent webmasters of their income" or whatever but I never, ever click ads. I don't read them, I don't like them, I disagree with them. I don't mind a text link or something but big banners full of "ZOMG CLICK HERE!!1!1" flashing images = big no. I won't block a text ad, but I will and do block images and Flash ads. If you want me to click things, make them unobtrusive instead of blinding me with flashings from all directions.
I am far too lazy to copy and paste URLs that aren't clickable into my address bar, so this handy extension does it for me. There is a better one but as yet I've not tried it and I'm happy with the one I've got, so I don't know if I'll use it.
Because I simply must know whether your site is valid or not. No, really... The most useful thing about this extension is that when you view the source of a page you're working on, it highlights the errors in the source and tells you what's wrong. It'll even tidy the whole thing up for you with one click if you want it to (yes, that's where the extension's library gets its name from - HTML Tidy - because it tidies things up for you. Get it? :P ).
This one is probably not as essential if you don't need to do screenshots or anything like that, but basically it will take a screenshot of the entire page, not just the bit that's currently on your screen. I like it since I can screenshot a full page of content (useful for people like me whose printer doesn't work and who want to save the current page they're on - yes, you can do "save page as" or print it to a file, but I think this method is quicker and easier, so that's why I use it).
Tamper Data stopped working for me when I upgraded to Firefox 2, but it's a great extension meant for detecting vulnerabilities in scripts. It's got SQL injection and XSS stuff built in and ready to go to test your scripts to the limit. Of course, if you don't write or use scripts or anything then this extension is a bit useless to you.
Of course, there are the other extensions everyone recommends, like the Web Developer Toolbar, NoScript, IE Tab, etc., etc., which are very useful and which I have, but like I said, everyone recommends those so I thought I'd mention some of the lesser-known ones.
Regarding the last entry, yes, I had written an entry about how my house seemed to have accumulated some bedbugs. That entry decided to disappear off the face of the earth and I have no idea why. Anyway, upon closer inspection it appeared the bugs weren't bedbugs, but carpet beetles and pest control won't deal with those without charging us some hugely expensive fee so I've just gone mad with insecticide and we'll see how that turns out. Urgh.