Ah you went to a few good spots then. De Barra's, while it says it's a folk club, has all sorts of music there ranging from traditional (usually Monday night in the front bar) to rock and roll. It's actually quite a famous venue and has a lot of big acts playing there. An Teach Beag (The Little House) is the place for consistent trad though. It's part of O' Donovan's Hotel right in the centre.
My favourite place however is Shanleys on Connolly Street. The original music bar in Clonakilty. In fact, they are celebrating their 120th anniversary the first weekend in August and I will be home for it. I just noticed today that they put my name on the poster along with a host of musicians so I guess I kind of have to go now...;) SHould be epic and I can't wait.
Clon is a great town though. As you say, it has quite the history but it is also a very progressive town that has come up with so many great forward-thinking ideas. The first town to do Fair Trade for example. And every June, they do a street carnival and take all the traffic out of the main street and put long tables down the middle of the road and various food and drink trucks to serve the people. Open to all. Fantastic event. And a couple of weeks ago, they had an old-time fair and vintage vehicle rally. I miss it it and maybe will retire there in a few years.
Sorry for the long post. Looks like I am writing an ad for the town...;)