Most of you guys probably already know this, but I do not use drive pedals very much. Anyway the Maxon OD 808 sounds really really good. Very natural and smooth. You can even use it with jazz chords! Very nice pedal for low gain tones, even if you are not trying to be SRV.
The Mad professor Little green wonder, and Zendrive are among my favorites, but color the tone a bit more than the Maxon. (In a good way depending on what you are looking for) The 808 remains the chords with overdrive king however.
