A band name should be something that people can remember in their head. If they can't pronounce it, they won't remember it. For that reason, I agree with what has already been said about using an Irish phrase for a band name.

I love Irish culture and music. I'm trying to start a band that exclusively plays traditional Irish music; however, I would never use an Irish Gealic name for such a band. 99% of the english speaking world probably wouldn't recognise it as Irish. Therefore, the name would not even come close to serving its purpose.

I have seen some exceptions. I saw a very good band that called themselves "Uisce Beatha". They seemed to have a pretty good following, but only because of the Clancy Bros.

-Racer