Appropriate Conference Attire?

We academics attend conferences. It's all part of the allegedly (according to FOX News) cushy lifestyle that we have in the academy. Whenever I go to a conference, I usually have a plan for my 10 pages of text. However, I usually don't have a plan for what I'm going to wear until I start packing to leave. While the business formal power suit is always an option in my field, I tend to go for dresses and cardigans these days, especially for smaller, regional conferences. I've seen an incredible range of attire at some of the conferences I've attended -- from the impeccably tailored suits (both for men and women) to beat up jeans, sneakers, and hoodies. How do you dress for conferences? Do you feel that dressing up or down helps you in any way with your paper presentation (and presentation of self)? I'm curious as well how the standards differ from the Humanities to the Sciences. So do share! What's your conference go-to outfit?