The Samsung Modus 3500 is a mono-to-stereo convertible headset. It has dual-mic premium noise canceling, a stabilizer loop for the ears, and comes in black and white colors. It will cost about $59 to $69.
The Samsung HM1500 isn't really a headset in so much as it is a clip with a ear bud hanging from it. It's another mono headset, and it's designed for those who like the convenience of a headset but don't want to wear one all the time. It will retail for $49.