Schallers, all the way. The various Schaller copies probably work fine too, but I'm a snob.
Everyone says Dunlops are good, but the locking mechanism goes inside the button and I had a set once which kept slipping out - they were, in fact, Strap Not-Locks. I don't trust them any more.
I'm sure the Grolsch rubber rings work well too, but I don't want to drink the horrible stuff to get hold of them.