Rypien for sure. On top of having absolutely vicious fists, he had a will that just did not allow him to quit. Being a huge Brad May fan i remember a fight he had with May where May got the jump on him quick, and having seen May finish so many guys off within the first 5 seconds i was sure it was over. May clocked him with a left that should have dropped him, but it was like it just flipped a switch in him and bam bam bam he completely flipped the fight and started going off on May. There's no way to see a guy with that will and not respect it.