Your present user figures speak for themselves. You certainly need to keep supporting IE6 until it's in negligable use.

The best way to solve the problem is to---from the beginning---only use techniques that are known to work everywhere, where 'everywhere' currently, unfortunately, includes IE6.

Since you've just done a bit of a redesign and it looks good from where I'm sitting ( Opera ); if I were you I wouldn't invest too much time making everything look perfect in IE6. Just get the functional part working ( you said the site is 'practically unusable' in places, so sort that bit out ), but leave any tiny visual discrepancies alone, or assign them a very low priority, and then just watch the user browser figures. Maybe in 6 months things will be different. Maybe in 6 months all those IE6 sufferers will find Opera ^_-

You know, Opera users may well appear as IE6 users. Personally, I always indentify as IE because certain sites refuse to open up to browsers that identify as Opera, so.. maybe your user stats are a little skewed by Opera users ( for which the site works fine ). Last time I looked at the browser ID string in this mode ( was Opera 8, sometime last year ) it was equiv. to the IE6 browser ID string.

ie7 is a high priority update in microsoft update. This is probably why the numbers are going down. I am not sure but I think aol still uses ie6 as their primary browser. old joke:How many Microsoft programmers does it take to screw in a light bulb? None. Let's define darkness as the new industry standard.