Get a 'cross bike because then you have a great commuter bike and can also do cyclocross races.

You might also look at touring bikes, but I definitely would not ride the Specialized you have. I'd go toward the steel bikes like the Surly or Volpe you mentioned. As for components, I think Tiagra is OK for general transportation use and you can upgrade after a while if you want something more performance oriented.

I've written more about selecting a commuter/transportation bike here: http://austinbikeblog.org/?p=38