744: If you want one last chance to fly on the 744 before it retires, then choose this one.
763: I think this option would go through ORD or EWR, because no 763s fly SFO-LHR. If you want a shorter TATL flight, then choose this option (7.5-8 hours vs 10-10.5 hours).
772: If you want a longer TATL flight (which is actually what I would personally want) and don't care about the 744s retirement, then choose this option.
Others may disagree, but I prefer 10 hour TATL flights over 7.5 hour TATL flights because I can watch a movie, eat, and still get a good night's sleep. So I would go with anything except the 763 option.