OK, I've strictly just finished learning this but...
Merry Christmas Everybody
On the grounds that (a) it isn't shite like most 'Xmas Songs' (b) The hardest part is the bass, meaning no one can complain it's too difficult and (c) I may be able to avoid having to play drivel or learn Dee Murray's bassline to Step Into Christmas (which is wasted on that song).
But seriously, what a great bassline, Jim Lea = underrated genius.