I am happy with these:
For Cool
Mid-Range
Cold

I got them in a "20% off, free ship over $49" sale that Nashbar frequently runs.

My helmet sucks in air that gets quite cool on the forehead, even on a 60 degree/humid day. The headband works perfectly to completely eliminate any cool feelings. They are all thin enough that my helmet easily adjusts enough to accommodate any two of them in combination.

YMMV.......I live in Georgia. The coldest temps that I have used them in was the low twenties.