For people who in large part claim that clothes really aren't important (a) we can spend a lot of time talking about it if prompted and (b) we seem to establish clothing norms in a way that suggests we're not as anti/immune to fashion as we might like to think.

The suits thing is a little different - that's usually a (somewhat reasonable) reaction to the judgemental side of what you wear = your competence. I have concerns when it goes too far (that people assume anyone wearing a suit is automatically a fool, which seems to me to be the same thing only in reverse).

But that aside it seems that most geeks use clothing in exactly the same way as most people - express personality, as a uniform, as a way of showing interest in other cultural phenomenon and so on.

We're usually not interested in "high fashion" but I'd be very sceptical about anyone saying that as a group we're not interested in fashion.