Can I legally be fired from my job all because I have a personal website that some might consider to be a bit risque'?

Absolutely.  There are only certain things that you can't be fired for.  Those things are generally tied to what is called a protected class.  In other words, you cannot be fired for reasons related to race, religion, gender, disability and a few others.  But outside of that, an employer can terminate your employment for any reason or no reason at all.  If you have a personal website that your employer doesn't like, and they fire you for that, you have will generally have no legal recourse.