There was a trend of inserting out of place modern sounding pop tunes into Westerns, which for me totaly pulls me out of the film magic. Its not at all period sounding or done live with extraneous sounds like it would be if live but sounding like it was canned and right out of a sound studio.
BC&TSK was the first one that I remember doing it, and I've since run into two more, The Life & Times of Judge Roy Bean, and Cahill US Marshall there are probably a few others on this list.
When its done right its fine, like Lenoard Cohen for "McCabe & Mrs. Miller", or Dob Dylan for "Pat Garret & Billy The Kid". Now the De Angelis Bros is a bit too much in Keoma with the female falsetto voice, but it doesn't bother me as much as it do some folks. ;D