No. Achieving the proper exposure requires knowing how to meter. Just using "M" and centering the exposure arrow doesn't tell anyone anything. Not centering the arrow is the same thing as using any other mode with exposure compensation.
Using partial metering with the 20D is a good option as long as the OP understands that you have to point the camera at something 18% grey, dial in the exposure, then take the shot. It's just as easy to leave the camera in auto and use AE Lock (* button) though.