What's your favourite song?

So, I want some more songs on my iTunes but I'm not sure of what I
want so... What's your favourite song? It could be like an old song
(old=Beatles, Whitney Houston that stuff..) or kinda new..

so yeah, thanks..
Different kinds are cool.. like country, rap, or anything (NOT heavy
metal.. I hate that!) I'm kinda trying to get to know different styles
of music..