I also like the fist pump. I think there are different ways to "raise your arms". You could be doing the Ryan Hall Olympic Trials raising of the arms to get the crowd pumped up, or you could be doing the "I finished and I am so happy" raising of the arms, or you can look like you think "I am the bomb" raising of the hands. I think raising your arms as you cross the finish line depends on how you are doing it. If you are coming in from a 5 hour marathon and you are doing the "I am the bomb" hand raise then that is pretty cocky and tacky but really, it is still a free country so I really don't care in the end...