Christina has many iconic singles like lady marmalade and beautiful in the us. But Shakira is most popular in Latin America. Although Hips Don't lie was a hit here and so was Beautiful liar , Christina has had more hits in the us.
Soo...
Christina:US
Shakira: Latin America
They're both iconic for the early 00's but I don't think they've really made a standing impact yet. I'd say Xtina has the edge in this one though just for the iconic imagery in her videos.
Do you honestly believe Waka Waka ***** on Beautiful? That song has only been out for like a year, and already forgotten. Waka Waka hasn't changed lives, united people from colors to sexual identity, get recognized for its impact on music lists, and talent shows, etc, etc, etc.