For the first issue you're going to have to revise your styling. You can't use .navMenu .m td as the selector because that styles all td's in the table.

To get your lines around the menu items, try instead to put a line on the left, top and right sides of the whole table and then only put lines on the lower sides of the table cells.

Your second issue is focus outlines. These are used by people who cannot navigate with a mouse and you should leave them in place if the site is meant to be used by everyone. User can tab through all links on the web page and have visual feedback with these outlines. Each browser colours them differently.

For some reason Firefox have decided they don't need them in 4. No idea why... maybe they are hidden away in an accessiblity setting somewhere.

If you want to get rid of them, look up how to style or remove focus outlines.

Regards
Rob

p.s. I've seldom seen so many different fonts on a single site!

Yes, make sure you look for a cross-browser solution for removing focus outlines. There are plenty around.

I came across that forms name issue on a random site just today in fact, but I haven't seen it on any of mine. My advice is to run your site in IE8 compatiblity mode for the next few months until all the IE9 issues have been resolved... there are all sorts of minor problems at th moment.

More on that here: http://msdn.microsoft.com/en-us/library/cc288325%28v=vs.85%29.aspx

You can put the meta tag in your default.aspx.. just remember it's there if you upgrade DNN... which I don't advise doing these days.
Regards
Rob