I'm rather 'surprised' no one's mentioned (yet) the huge 2000 Carlos Santana hit: "Smooth", as it's actually based on a Cha Cha rhythm, and can easily be adapted & performed as a ballroom Cha Cha as well.
http://mfile.akamai.com/3171/wm2/muze.do....asx?obj=v10207

Scott