Dress the part.

thenewgreen and I have talked about this, and I think the caveat is that not all parts call for a suit. Most important to me, is someone that knows their business. I wouldn't buy a tractor from a guy in a suit. I would probably favor employing a male banker wearing a suit to one that wasn't, but if I were hiring a male coder, a suit would make me less, not more, inclined to hire him.

I used to go to the American Stroke Conference every year, and it was interesting because the MD men were almost all wearing suits, and the male scientists were almost exclusively not. Male pharmaceutical reps were all in suits. As a scientist, suit-wearing doesn't give you credibility, if anything, it can do the opposite because you aren't selling for financial gain and a suit can give the impression that you are. Physics conferences are an extreme, you can find very successful people in sweatpants.

I wear a suit for weddings, funerals, and banquets. I would wear one for some interviews, but if I were interviewing for a science position, I'd probably go with a suit but no tie, just so it's clear. I don't terribly mind wearing suits, and even enjoy looking smart in that way from time to time, but I would not long stay in a position that required me to wear one daily. Same goes for a cowboy hat.

There is also the issue about suits and gender, which I am not a fan of. I wish guys could be considered smart-looking without such little variation.