Basic Arduino Variant for autonomous bot?

Hello i plan to assemble a bot, though i got 1 arduino duemilanove and 3 x Atmega328P so far.

I need like 2 servos for the wheels, 2 for the arms and 2 for head movement - so up to 5-6 servos.
For sensors im not sure yet what would be easyer to implement and code to start off - IR or Sonar(like Parallax Ping)?

Would it make sense to get a roboduino board, in case i missed something and to prevent extending the board later. Or can i use the arduino basic board first and with atmega328P?

Is the duemilanove with atmega328 comparable with the Axon Microcontroller C-400 Axon?

Many questions, thanks for any suggestions.