I use the Avantree Jogger Sports Bluetooth Headset. Works pretty well. I would recommend it. You may occasionally get an audio drop out (of a second or so) under certain conditions, but that can happen with any BT device. And it seems to be pretty rare with this one (compared to friends who have other models). And it easily makes up for losing the chord. Frankly, once I have the headset and arm band situated, it's pretty drop out free.
Armbands are all a little slipshod, but I have the Arkon Sports Armband. The touch screen operates fine through the protective plastic cover. With the phone, it seems a bit heavy (compared to small mp3 players I have previously used), but I eventually found that putting it a bit further up my arm made it pretty comfortable.