Svetlana Loboda is really good.. she's not really ethnic or anything, but she has a good voice and is a lot of fun
Mishka
If you wanna get more experimental and ethnic, the Ukrainian Ruslana is definately worth checking out as Kaiouforever said. She won the Eurovision Song Contest, which is the biggest TV event in the world with the song "Wild Dances". She incorporates traditional instruments into modern music which is cool.
Wild Dances