Choirs abound, and among the best is Cantus Bratislava. Since its establishment in 1984, this choir has been led by professionally trained musicians while its fifty-plus members have been amateurs whose voices are honed and blended into a magical whole. They perform a varied repertoire: church music of many periods, classical music, Slovak folk music, and Negro spirituals. Cantus is very dear to my heart, for they performed at the release event for Moje Slovensko, moja rodina held in the Pálffy Palace of Bratislava in December of 2010.
You can read about Cantus, in both Slovak and English, at: http://www.cantus.tym.sk/
A number of videos from one of their concerts in 2010 can be seen on YouTube; just search under “Cantus Bratislava.”