Okay, my first thought--RUN FAR AWAY FROM MILEY CYRUS. There are plenty of happy songs without resorting to her...gah.
Ahem. Anyways, I would recommend these songs/artists for happy music:
Funhouse-P!nk
Bad Influence-P!nk
Lots of Lady Gaga
Bob Marley!
Cherry Lips-Garbage
Band of Skulls (not all of their stuff is sad)
Red Hot Chili Peppers (their earlier stuff is quite beat-y, but Californication and the like are very lyrical though a bit sad)
K-OS!
Brendan Benson
Lily Allen
Tegan and Sara
The Killers
That's all I got.