I am looking for all time classics for my Ipod but don't know where to start - any suggestions?

I've been trying to find good songs to put on my Ipod from a range of
genres but I can't find any good ones. If you have any albums or songs
please put them on or if you can't think of any classics then please
just put your favourite song. For example - mines Chelsea Dagger by
The Fratellis.