Good clean code means forward compatable and the only reasons not to use valid code is you are paid by the hour or you dont know how. The first I cant do anything about the second is easy to take care of. I have not seen any writers on web design or CSS recommend invalid, sloppy code and I think they know more than I do. I make a darn good living cleaning up after someone that calls themselves a designer. My editor of choice is notepad or a free editor that allows me to write clean code. Clicking on a button does not make one a designer. Web standards is the only way to design.
Don
Seopro