You can't go wrong with Knockin On Heavens door.
One I also played at the beginnning. If you like Floyd at all, Pigs On The Wing is a nice one to get to grips.
Trip Through Your Wires and With or Without You by U2...Infact there are many easy U2...Van Diemens land, Pride and Where The Streets Have No Name are ones that spring to mind.
Then there is Waiting In Vain - Bob Marley...A nice easy G to C
middle 8 of C to D to Bminor then C again x2
I shall shut up now!!! lol