Last night I installed the newest version of Firefox (2.0) and just now I noticed that it checks spelling in form fields!
What a wonderful feature! This might be a good reason to switch to using Firefox as my main browser (currently I’m preferring the good ol’ Mozilla). I had a list somewhere where I’d written reasons why I haven’t switched yet. I’ll have to look it up and see if something is still holding me back.
[edit Oct 31st]
There is at least one thing: I haven’t found a setting for “Autocomplete best match as you type” which is Mozilla’s Location Bar Autocomplete feature.
Also, why doesn’t it select a link when I search for text?