I'm thinking I need to become a farmer or something and stop trying to make websites work for every browser...
Ok, well, I tried implementing the CSS changes you suggested, but they don't seem to help, sorry to say.
I've modified the menu_ie.css file (with help from you, neilo, in another post) so that it works perfectly with IE6. I changed the conditional statement to include IE7 or later, and made the changes you suggested. You can see an example of this here: contact.php (it's the only page i've changed the conditional statement for).
If you use IE Tester or crossbrowsertesting.com, the top nav looks and works fine in IE6, but then falls apart in IE7 for some reason.
The first thing I noticed is that IE6 seems to 'ignore' line 29 of menu_ie.css (under cssmw1) which sets the list item width at 80px. Why this is, I have no idea, but it didn't cause a problem rendering in IE6... but if I increase the value, it DOES cause a problem.
I bring that up because IE7 seems to actually apply the 80px width, as you will see! But... that's not even the main problem. IE7 also is creating a gap between the main list item, and the dropdown menu!! So, back to where I started, in that the dropdown menu doesn't work... because of the gap now you can't get to it.
I'm thinking at this point that I'm going to leave the original menu_ie.css for IE6 and earlier... and create a separate IE7 css style sheet... but... I still have to figure out how to get IE7 to render the menu properly!!
I've been sitting here for four hours trying to make changes to the css and get it to work, but so far I've had no luck... thus another post in the forum! ;)