I second the recommendation for ex officio underwear. I've found, however, that the Jockey for Her microfiber French cut briefs dry just as fast and can often be obtained cheaper on sale.

I have never found any socks, no matter what high tech material, that will actually dry overnight in most non-desert climates. I'd like to think that the various cool-wick synthetics would, but I've not had any success with at least 5 or 6 different brands I've tried. Usually, I can get away with wearing my Keene sandals without socks while I am waiting for the socks to dry, but it is a pain if I am moving on every day and have to pack damp socks.