Might try "Let's do it". Joan Jett and some dude. Has a touch of punk to it, like all her songs.

roadside - rise against
:)

The Subways are amazing. Pretty much anything by them have a guy and girl singing, and its great.
http://www.myspace.com/thesubways

This song is probably closest to what youre looking for
http://www.youtube.com/watch?v=TLIquztdlnw&feature=related

Most of these aren't really punk just indie
Here are some bands and songs:
Stars
The Postal Service
Belle & Sebastian
Nothing/Nowhere by Clare and the Reasons w/ Sufjan Stevens
End of the Affair by Johnathan Rice & Jenny Lewis
The Moldy Peaches
She & Him
Mates of State
The New Pornographers
Stop Draggin' My Heart Around by Tom Petty and Stevie Nicks
Yankee Bayonet by The Decemberists
Modern Girls and Old Fashioned Men by The Strokes and Regina Spektor
The Weepies

Mates Of State
The Postal Service
Ranier Maria
The Pixies
Cibo Matto
Camera Obscura
The New Pornographers
Rilo Kiley on a few songs.

listen to = Los Campesino's - You! Me! Dancing!!!!!!