I'm still sitting on the fence and haven't bought another pair yet, but I'm leaning toward the Nokia BH-505, which claims to be sweat-resistant. Since I'd wear them a lot while working out, that'd be a handy feature. It was a drawback of the Motorola S9, which was definitely not sweat-resistant. The Plantronic sounds wonderful, but they don't look comfortable to wear while working out.

Thanks, all!