I have found this tutorial written by Fupster to be quite an excellent concept and could lead to a more complex and capable AI should enough time be put into it. It incorporates the use of Neural Nets and Genetic Algorithmns together. I have managed to start writing a mostly functional AI unit based on this concept, but I have also seen someone else get the clone of the example written by Fupster to work quite well. All the code in the tutorial is in C unfortunately, but you can make most of it out well enough(the Delphi made example hosted on the site does not work and is not the example I mentioned just now).

http://www.ai-junkie.com/