Other people have covered the construction of the site pretty well, so I'll focus on your organization and visual flow from a business standpoint.
1. People who buy stock / commission photography are extremely busy. As that type of person, the first thing I want to see is your work, but on your site it took 3 clicks from the home page before I could really see anything. You need to show work right away so I can decide if your skill set/style is right for my project.
2. I think its very true that your only as good as the Worst work you show, because thats where people will base their judgment. Your gallery itself is way too big and doesn't have a focus. The use of the simple viewer is good, but I had to choose from several "preview" images before I ever got to see actual work. I would slim down your image portfolio. The typical rule of thumb is 15 to 30 of your very best images without the categories. I would try to select images that show a specific technique or style since an industry like photography is much to crowded not to focus on something specific. In other words become known for a style; make that style your calling card and don't show the rest unless someone asks you for it.
3. I'd get rid of the map of visits. Its kind of fun to see that information for yourself, but your visitors probably don't care and it takes away from space on the page that you could use to show off how great you are.
4. Finally, a pitfall that I see very frequently is that people want to sell their services, but don't provide that information to their visitors. I say you should "tell" people that you want to work with them. It can be as simple as some text on the home page that says "Now accepting assignments. Here's how you can contact us." The problem is that most people will not "offer" to work with you. They don't know if your busy, if this is just your hobby and you don't do commissioned work, etc.
Now don't get me wrong. I like your site and your work, this is just some criticism to help you grow your hobby into a business (per your posted goals above).
If at first you don't succeed F1... If that doesn't work try Google!
//// Designer, Developer & Teacher - Interactive, Motion and 3D \\\\
Portfolio at WhenImNotSleeping.com