Globaly, yes. But if you want, per example, to target China, IE6 is mandatory. http://www.ie6countdown.com/

(and even Japan is at 4.7% according to this site. 4.7% is significant enough.)

Mandatory? For everybody?

There's a cost to supporting IE6, and a cost to not supporting it. Depending on what you're doing, it might make much better sense to do something like:

http://code.google.com/p/ie6-upgrade-warning/

IE6 usage is falling fast, even in China.