Murtagh was a character in Christopher Paolini's "Inheritance Triligy". Murtagh is one of the good-guys at first, but later after being captured by the king, he becomes a Dragon Rider and betrays them all. I totally had no idea this was a real name; I thought Paolini just made it up. I only looked it up on the off chance that it was real name.
Yes, I too had no idea this was an actual name. I wonder if the others are actual, too. I, for one, love this name. Murtagh was my favorite character, until he bacame evil. I doubt he will stay evil, though.
I like this name a lot. It's unique and grossly unpopular. But it would look really weird on a name tag at work. Still, I'd consider using it on a child, but I don't want to ruin its good record of not being used.