Legacy played music during our one and a half our cocktail hour. They played traditional Irish music. SEVERAL of our guests have mentioned specifically how fun it was to listen to the music while drinking their wine and chatting. The band did a... great job with sound (not too loud, not too quiet) and kept things going with appropriate pauses between songs. We were lucky enough to catch the end of their performance, and we caught many guests tapping their toes.
If you want something a little different, or a touch of Irish culture and heritage, I would recommend Legacy or their slightly different band, Forty Shades of Green.