Czuch Czuckers: Just one :)

NoScript ( http://addons.mozilla.org/firefox/722/ )

"Snoopy": Shift key stuck?
Touch all Shift, Ctrl and Alt keys and make sure they're all unstuck

or

unplug the keyboard from the computer, throw it hard, keys down, against your bed.

"Snoopy": Lots of them (and a whole lot of other types of software):

http://www.econsultant.com/i-want-freeware-utilities/index.html
http://www.econsultant.com/i-want-open-source-software/index.html

Sorry, I can't recommend one of the "Anti-Spyware/Anti-Virus/Anti-Rootkit" because I don't use them (my connection to the internet is through a Linux machine which has its own firewall).

Czuch Czuckers: Do you mean version 3.01a (screenshot ) or maybe 3.0a2?
I installed that version on my work computer; now I have both version 2 and version 3 installed and can run either depending on which icon I click (but I'm not running the "Minefield" version).

Anyway, barring extension/configuration problems, I believe you can uninstall all versions, download the version you prefer, and install only that version (maybe you'll have to reinstall extensions too).

MadMonkey: Search your disk for files larger than ... errr ... 2Gb! If you don't find any, try a smaller file size :)

Identify what program is writing to those files and disable that program.

... I suspect some kind of logging.

Mr. Shumway: FF 3.0a1; I even have a screenshot :)

But if you have a lot (or a few) extensions, don't install it ...

Rose: What extensions (or addons) did you install yesterday?

The RTE (Rich Text Editor) is a JavaScript thingamajing, to use it you only need JavaScript enabled; some extension may have disabled it.

[Edit] Try disabling extensions one by one until the RTE starts working again.

Binabik: That ...\Firefox\Profiles was just a guess. Have a peek at Firefox Help: How To Manage Profiles :)

I don't know if your Firefox is automagically generating profiles for each new installation, and if it is I don't know why or how to stop it from doing that, sorry :(
Anyway, I thought it wouldn't hurt to see there.

Binabik: Are you on Windows?
If you open the folder C:\Documents and Settings\YOUR_WINDOWS_NAME_HERE\Application Data\Mozilla\Firefox\Profiles\ (or some such) how many folders do you get? Should be 1! If there's more than 1 folder you may be able to fetch your bookmarks from a "old" folder to the most recent one.

Close Firefox before moving files within these folders.

Baked Alaskan: Is that the "Walnut Theme"? From the Stephanie's comments in the User comments there, I believe version 1.7.0 does not exhibit that behaviour.

Maybe you should update it? Try Tools/Add-ons, select Themes and click "Find Updates"

Baked Alaskan: I believe it's because of the size of the icons on that "line". I can't reproduce it here (screenshot 1), but with a few tweaks to my userChrome.css file (screenshot 2, notice the path to the file) I got something similar (screenshot 3) :)
... maybe you can change your userChrome.css file to change the size to something you like.

gogul: I didn't test the Tab To Window add-on, but it appears to do what you want.

BIG BAD WOLF: Thank you for fishing that tabMinWidth setting for me :)

With my setting (screenshot), I found out I can close tabs with a middle click on the tab (just like if it had the close button there too) -- I find myself closing tabs this way a lot of times!

ellieoop: with the mouse: Ctrl+mouse wheel
with the keyboard: NUM<+> to zoom in; NUM<-> to zoom out

You can find more shortcuts at the Opera features page

Hrqls: Can you try converting those 8 bits you send/receive to 7 bits?
I googled a bit and found a Base64 Encoder/Decoder, but maybe the .NET framework already has something similar ???

volant: I haven't tried it, but maybe the Linkification extension will do what you want.