The company I now work for (A large ISP in the UK) has the most sensible dress code I've yet to come across.
"Dress Code:
Both you & your clothes are expected to be clean"
This seems to work - we have a huge variety of people doing a huge varietyof jobs & we were all hired for our ability to do the job not for how good we look in suit.
No one is too scruffy (although I guess everyone's definition of that is different) and most people will dress according to what they are doing that day.
Having said all that, I'm sat here in jeans, t-shirt & a hooded sweatshirt. But I'm comfortable & more productive (I like to think!)