I have to be honest, I don't think a handshake makes a difference. I have played plenty of people and not thought of giving a handshake at the end. I remember thinking it was weird having some guy I just beat or lost to walk up to me to give me a hand shake. If, through the match you are respectful of the opponent and in winning you are respectful and in losing you are a good sport, who cares about a hand shake. I personally don't really want the guy who won coming over to me to give me a handshake. If he lost and is doing it, that is fine with me. But it does not matter to me if someone comes up to me after a match to shake my hand or not. And, I feel much more comfortable walking up to someone I just lost to to give them a handshake and say "good match" than walking up to someone I beat and giving them a handshake. Truthfully, the winner going for the handshake seems a little patronizing to me.
And there are lots of ways for the loser to congratulate the winner aside from giving a handshake. Personally, I don't know why so many times this issue has come up and why so many people think that in sport you need to be a gentleman. I like to joke about the bad boy players from other sports talking smack and being rude, but I don't think sport needs to be overly polite.