the times, they are a changin'
breakfast at tiffany's (assuming you can still stand it after the initialy beating-in on the radio)
+1 for mustang sally (chorus has a good echo)
ELVIS

Hound dog (12 bar in C), Heartbreak hotel, Jailhouse rock, Blue suede shoes, etc... So many good easy songs that people don't even realize they know until they sing along.
House of the rising sun
I like simon and garfunkel. Most of their stuff is too sedated for groups to enjoy, but 'the boxer' and 'mrs robinson' usually go over well and are fairly easy to strum. 'Feelin' Groovy' (the 59th street bridge song) is a good one, since it's short.
Country roads
leavin on a jet plane.
Bye Bye love
Wild thing
+1 for peter paul and mary. Puff the magic dragon is pretty easy (A, C#m, D, A, C#m, D, E). I used to tease my friend who likes ska (punk version) that it derived from puff, and proceeded to play it in the style to piss him off.
Ramblin' Man
I recently learned 'Basketcase' by greenday the other day and it goes over pretty well for people who like that sort of thing.
Wonderwall (oasis)
Sweet baby james
