Quote: "(relatively) few number of machines out there"
I think that's the whole point though. It isn't a few users (even relatively), it's tens of millions. I used to think the same way as you, why bother building for any other browser, wasn't IE a standard in itself? A few years ago I think it was, but it has lost significant ground now and with the changing disability access laws and the, well, common-sense displayed in the various sites above, it just isn't worth thinking like that any longer.
Oh and I'm a Firefox fan-boy
"I am not young enough to know everything."
- Oscar Wilde