OT: How do you xhtml/css2 guru's treat NS4?

I have been following this list for sometime and attempting to put much of
what I learn into practice. I must say that much of it has been very
helpful. I have noticed, and this is no surprise, that most of the
suggestions do not render very well at all in NS4. I also know the reasons
for this.

My question is, what do you guys do?
- Ignore Netscape 4
- Build a duplicate site/style sheet and use some browser sniffing
- Only use code that depreciates gracefully

I am just interested from a practical point of view.

Cheers

Mark