Hard to debate.. Although, Mace had Sidious defeated and trusted Anakin too much which led to his demise. Had he known Anakin would come to the aid of Sid he may have defeated him and then Anakin afterward. Yoda struggled a bit when he battled Sidious 1v1 at the end of Episode III, but it's tough to deny Yoda the number one spot. As far as Anakin versus Obi is concerned, I believe at that time they were both about equally as strong. Anakin was just a bit too cocky and that's what cost him the battle at the end of Episode III. The person who had QGJ listed needs to remember that he was defeated by Darth Maul. I would probably rank them:
1. Yoda/Mace
2. Anakin/Obi
3. Luke (with the limited knowledge we have)