Ladies and Gentlemen, it's difficult to believe that so much heat can be generated over whether or not to wrap a bit of fabric round your neck. When I started work as a tender 21 year-old professional (ie graduate) electronics engineer it was necessary to wear a suit and tie - but that was in 1976. In 2005 there are VERY few professional organisations in the more progressive areas of industry that still expect a tie (and many are happy with Jeans, or even shorts in the summer) - people are assessed on performance. A monkey in a suit and tie is still a monkey.
There's value in wearing some sort of "uniform" (white shirt and dark trousers) just so that staff can be identified but logo-ed sweatshirts would be as good.
BTW, ref Beags' comment, I'm sure there was a joke of sorts from my pubescent years that ended "but she knew what wedgi meant" - anybody know what it is?