I'm kind of on the fence about Safari for Windows, but one of the truly great features is to be able to resize the text fields in any form.
Turns out there's a Firefox extension that lets you do exactly the same thing. It's not as 'pretty' as the Safari version, but it works just as well.
Sweet.
Update: It appears to do one odd thing in that it lets you resize drop down boxes, but in doing so, it changes them into list boxes, which is somewhat bizarre.