Solo female traveler here, eat out alone at restaurants all the time and enjoy it. A high top table inside the bar area of the restaurant is perfect -- I can people-watch and meet other diners, but I'm not trapped talking to someone for an entire meal like I am sitting at the bar.
Two minor pet peeves:
- The "just one?" question mentioned above
- Being seated alone in a room or in the corner of a room like I'm a leper
My best experience dining solo was taking notes in a Michelin 3-star restaurant in San Sebastian, being mistaken for a food critic, and being treated to a private tour of the kitchen by a famous chef:
http://www.esmetravels.com/arzak/