Thank you very much jims and mellis for the quick and very helpful replies!
@mellis: I think it would be a good idea to keep up the support for PINS 14-19 in the arduino(wiring) language.
For my current project for instance I do not need analogue ins, as I am using MIDI to drive my servos and LEDs.
In another thread (http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1160661590) there is btw a hint how to switch serial ports to have at least 13 digital out.
--> So maybe this hidden feature (using analogue-in as digital in/OUT) should even become an offical one in the future???
PS: I'm using my arduinos for only 3 weeks now - and having so much fun, the Hardware, the Software and the discussions going on in the web (espacially at www.arduino.cc/... of course) are just great!