It's all how you market yourself and who your target clients are. I target small-medium businesses and present myself as a "one man bad" of sorts, no overhead so i can price myself a bit less than an agency but a higher level of service and a solid designer-client relationship.

When they talk to me they're talking to the person working with them on their site. Not a salesperson or manager or senior designer who's not going to do the actual work. My repeat clients (especially ones with previous dealings with agencies) really seem to appreciate this.

If you have 10 years experience you already have a name you can trade on, i think trading on your own name gives a more personal experience to the client. Like Salathe and julian said, why pretend to be something your not?

A professional looking site is a professional looking site regardless of what name is on the header