As it turns out, Microsoft really doesn’t care about web standards at all. It has taken them way too many years to adopt the basics of CSS2 correctly. Now they are trying to expand that with IE8. However, developers still have to deal with the outdated IE6 and IE7. Using min-width is completely pointless unless your user base only uses good browsers.
The other day, I literally stumbled upon a JS file that fixes most of the IE6 and IE7 bugs. It emulates a lot of missing CSS functionality, and also applies a generic PNG fix. You can find the file here. I have been using it on all of my projects recently. In combination with a css reset stylesheet and the IE7 JS file, I have had a lot less headaches. I say you give it a shot. it’s not like it will take a lot of work for you to at least try out.