I want Here Comes The Sun by The Beatles. I'm not even a massive Beatles fan, but I just think this song is pretty apt for such an occaison
Also, what's the procedure for telling people what you want played? Some people die young, so have their parents just assumed what song they would have wanted. Some kid in our year at school was killed when he was about 15, and his parents chose to have Masterblaster 2000 by MC Luck and DJ Neat. Now, I'm not saying he didn't love that song... but really?
So yeah, either Here Comes The Sun or I'm Still Standing by Elton John