Hello!
My first instinct is to say,
AXON, but I have not had much luck with the coding and construction,
yet. To answer the question from beginning to end,
form follows function. Simple robots should be
simple to program and assemble, and thus, my recommendation follows;
My honest opinion, at this time, is to go to
Parallax. com. They have very simple basic stamps,
easy to program, put together, understand, and plenty of support.
PBASIC is the language they use. The Parallax propeller is more advanced, and has root languages that can be used together.
Good Luck!