What's the best thing you can say about a sweatband? Well, one good thing is to say that it does a good job.  I just started running this year and with the heat and humidity in Texas, it's not comfortable to have perspiration running into your eyes.  I asked a friend what he used and he mentioned the Halo Headband.  This headband is lightweight and non-constrictive.  It doesn't make you uncomfortable to wear it, with or without a cap.  Between the absorbtion characteristics of the slightly elastic material and the thin rubber "gutter" above your eyes, you can beat the heat comfortably.  Any moisture that isn't absorbed and evaporated, is channeled to the sides of the head, keeping your eyes clear.  I'm pretty sure I'll be coming back for more of these down the road.