Personally, I prefer a very minimalist card - I think it looks more professional. Like Sega - yours is very playful and attractive, but is that still professional (no offense)?
Yes! It's professional. No offence taken. There is nothing wrong with being playful, after all web design should be playful. There is nothing wrong with having a simplistic design either. It all depends on your companies image.
What does matter is having a design shaped to your business, and not to boiler-plated stock. This is the point I want to make. I really love my design, it's always a pleasure giving my cards out and it's certainly something you'd have to do when you start out.
The only issue with business cards is that people take them then they save them until the remember they have to call you. Often you might give a business card out years ago. This is why the details on those cards are crucial as well as the design.
On another topic, serious more professional approaches to your business are cool, but in web design I feel it's better to be playful with your image as it separates you from the herd. I don't have any regrets on my decisions and I hope that you find my advice useful.