One thing that I have not seen mentioned is that Professor X has the ability to project his consciousness to the astral plane, the same as Dr. Strange. He also has the ability Mind Possession In which he can take over someone's mind and use their body as his own. I have always believed this to be his greatest ability and greatest strength as a hero. See Professor X list of abilities here.

One thing that I have not seen mentioned is that Professor X has the ability to project his consciousness to the astral plane, the same as Dr. Strange. He also has the ability Mind Possession In which he can take over someone's mind and use their body as his own as well as mind transferal (Mind Transferal: able to transfer both his mind and powers into other host bodies if his own physical body could be somehow killed.) I have always believed this to be his greatest ability and greatest strength as a hero. See Professor X list of abilities here.