Choose just one song?! Impossible! I have so many favorites.
My fav that I'm listening to right now is Why Georgia by John Mayer. I love his music.

I'm also listening to Someday We'll Know -New Radicals
Ignition remix- R. Kelly
Where's the Love - Black Eyed Peas

Some all time favorites...
Lovin' Each Day - Ronan Keating
Walking on Sunshine - Katrina & the Waves
Anything by Rascal Flatts, Pat Benatar
Total Eclipse of the Heart - Bonnie Tyler
In Your Eyes - Peter Gabriel
Micky - Toni Basil
Can you tell I like 80s music?!

There's many more, but I can't think of it right now. I'd have to look at my play list on my home computer.