Get yourself the CD Song of the Crooked Dance. It's a compilation taken from Bulgarian vinyl from 1925 to 1942 - sort of like Bulgaria's answer to the Harry Smith Anthology - put together very nicely by Lauren Brody, and it's on the Yazoo label.

The Australian band Mara! does modern takes on traditional Bulgarian on most of their albums. The albums I'm most familiar with are Don't Even Think and Ruino Vino. I'm not sure how easy it is to get these outside of Australia. Australia also has a woman's a cappella outfit called the Martenitsa Choir - I think they are on the Tall Poppies label.

Some more Australians: Silvia Entcheva was in one of the top choirs in Bulgaria, but now she lives in Australia, and has put out a couple of albums. She has a superb voice.

For sheer energy, it's hard to beat Xenos. Their albums usually have a mix of music from various parts of the Balkans/Eastern Mediterranean, with a lot of Rom and/or Macedonian. They're also Australian, and again I don't know how easy it is to get their albums elsewhere.