The perfect domain name today might not be the best name tomorrow. Really think about what you want your domain to say..if anything. Don't corner yourself in by your domain name. I am sure a variation or a unique name is avaialbe. Take that perfect domain name and play with it and see what comes up. You might find an even better domain at the standard registration rate.

To really answer your question I would have to weigh the cost(are we talking hundreds, thousands, tens of thousands?) against the return. Is this the most common word or phrase for your service that a user would search for? Or is it too generic?