Personally, I've always worn whatever I want to work. I totally agree that "people should be judged on merit" and not their appearance - at least, if their appearance has nothing to do with their work (sales staff and management should definitely be smart at least, as they have to interact with people who care about that kind of thing). I worked at one place where I was required to wear a suit and tie (Tesco in Prague as an AIX admin) for three weeks before I quit. This is not just because I had to wear a suit every day - that was just a symptom of the underlying attitude of the place. It's because of all the rest of the ideas that go along with wearing a suit - things like not being able to dye your hair purple or wear earrings or come in at odd hours of the day because you've been working until 2am the night before. If you're in a job where you're not allowed to do this kind of thing, especially where it's in no way related to what you're actually doing, you are having your freedom taken away for no reason.

(btw, Ovid, if you're reading this - I'm not saying that people should quit their job because they're required to wear a shirt and tie; I just that it's sad that it's ever the case that people should have to do this for no real reason.