That's rather judgmental of you... I thought the whole point being driven by every crunchy, sandals-wearing startupmeister here was that clothes don't matter. How bigoted to immediately dismiss someone for dressing differently.

It's really just a tool like your editor. I personally dress for expedience. There are some forums where i have to go to where power dressing really does have a positive outcome. There are some places (eg. code sprints) where a T-shirt and an old pair of jeans works better.