Yay ska! I had a ska band in high school, my buddy's brother was in Reel Big Fish at the time and we really tried to emulate their sound. I transferred over all my old ska cds when mp3 players hit, and I still listen to them from time to time. As already mentioned in this thread, Op Ivy and Mighty Mighty Bosstones are the best them. For traditional ska I would suggest Hepcat, or the godfathers of the genre, the Wailers.