Best bitrate is 320Kbps CBR. Second is V0 (formerly known as AltPreseteXtreme) VBR

Their arguments have to do with size vs. quality, where VBR obviously is better as 320CBR would encode complete silence at 320Kbps.

And CD quality is none of the ones mentioned. 320CBR and V0/APX come close, but the only way to get CD quality is using a lossless codec like FLAC.