Best quality, IMO, is a stereo headset. Best overall that I have used is, believe it or not, is the inexpensive behind-the-head stereo item from BestBuy's house brand, Insignia. About $40. Very good battery life, good quality speakers and I have not had any complaints about the voice quality when I talk. The ear pieces are on-ear, not in-ear or over-ear. Mic is integrated into the leading edge of one of the ear pads.
I also have an overpriced Plantronics in-ear style with the mic on a control pod on the cord (cord goes around the back of the neck, I tend to use only one ear piece when using it for phone use). No complaints about my voice with that one either, but the fit is a bit fidgity in my ears, so the sound quality into me is a bit lacking. And the battery life suffers because the battery is so small.
I have tried several single-ear headsets, and IMO they all suck. Several are good to start, but they all degenerated quickly in one way or the other. In this style, I've had multiple models from Plantronics, Jabra, BlueAnt and Motorola. All were $50+, most were $80+, one was ~$100.