I always wondered what was more time efficient between using an IE6 stylesheet for every bug I see, or try to track down the problem in my website. Most common bugs can be solved without using css tricks. I can pretty much say that half my ie6 css bugs are in fact small errors in my coding but that got fixed by newer browsers automatically.
I rarely use an IE6 stylesheet mainly because I learned most IE6 problems and do workarounds before testing on it. I think it makes my templates more solid that way. When I know this template works on IE6, IE7 and Firefox without the use of IE stylesheets, I know it will probably work everywhere.
I know the IE png fix needs to be achieved in some way, but what i’m talking about is every small glitches we see in our templates that, in general, are caused by a bad calculation somewhere.
The thing is, knowing IE6 is a pain in the ass and might soon be a legend from the past. It might not be worth it, but it did made me saw some flaws in my CSS style.