I've turned several fans onto Powerpop lately.  One was into harder stuff, so I pushed the below, figuring it was a nice step into the genre:

Sam Roberts Band "We Were Born In A Flame"
Eugene Edwards "My Favorite Revolution"
Myracle Brah "life on planet eartsnop"
The Shazam "Godspeed The Shazam"
Alva Star "Alligators In The Lobby"
Brendan Benson "Lapalco"
Fountains of Wayne "Welcome Interstate Managers"
Splitsville "Repeater"
Matthew Sweet "Time Capsule (greatest hits)"
The Getaway Car s/t
IKE "Parallel Universe"
The Posies "Frosting on the Beater"


When I want them to expand on some of the more melodic stuff, I go with:

The Grays "Ro Sham Bo"
Jon Brion "Meaningless"
Jason Falkner "Author Unknown"
Elliott Smith "Figure 8"
Brad Jones "Gilt Flake"
Joe Jackson "Volume 4"
Owsley s/t
Odds "Bedbugs"
Jim Boggia "Fidelity is the Enemy"
Ben Folds Five s/t
Rhett Miller "The Instigator"
Aimee Mann "I'm With Stupid"

And when I *really* want them to take that next step, I push:

World Party "Egyptology"
XTC "Skylarking"
Umajets "Demolotion"
Cloud Eleven "Orange and Green and Yellow and Near"
The New Pornographers "Electric Version"
Starclock s/t
Splitsville "The Complete Pet Soul"