I can't believe someone else mentioned "Woke Up This Morning" by Alabama 3 as a samba! I've always listened to it and thought it sounded like one, and then stopped myself thinking...it can't be. I guess I'm not completely off-base!! I also like it as WCS.
On another note (yes, I know...it's late), I love "Pon de Replay" by Rihanna as a samba. But for lessons my teacher and I also use it for a quickstep. At first I thought he was crazy, and I felt like I needed to realign my brain. But now I LOVE it for quickstep.
I do a lot of audio editing (including music) for clients. I use the predecessor to Adobe Audition (Cool Edit). With my background as a musician, I can usually make edits that sound seamless. I can also use Cool Edit to increase and/or decrease tempi as needed (increasing usually works better), even without affecting pitch.