An easy one that goes down well is West Nashville Boogie by Steve Earle. Good opener to warm the band up & get past any nerves & the chords are E (for 1 1/2 bars) G, A.
Ice Cream Man by Van Halen is a pretty easy song too (just make guitarist do a solo to his ability tho to save embarrassment).
Take Me To The River by Talking Heads (or Al Green if you prefer).
Break On Through by The Doors.
Shy Boy by Talas, has a nice bass solo for you to learn.
Lean On Me by Bill Withers, just for a singalong & the cool wee bass bit during "Just call on me brother, if you need a hand".