I always use Yowie's from Cool headphones - wireless earbuds for ipod & ipod shuffle headphones - Outdoor Technology
They are cheap, effective, and look better than a bandana.
I have one Airhole mask but I just can't get over the similarity to a restroom glory hole. So I don't wear it, plus I got it for free so....I rocked it once......and then came the jokes....lol. Cool graphics though....maybe I just have retarded friends. Hahahaa