One final thing to put on and I'm done: three buttons. Any way I could fit these in as a left, right, and select button for an interface? I believe I'm beginning to run out of room.
I would have:
2 photoresistor sensors
1 RS232 Shifter board kit (see uart tutorial)
1 LCD screen
I haven't ordered anything yet, so if I need something larger in terms of microcontrollers I can get it. I'll just need to know how to substitute the 8 with the new one in the $50 robot circuitry.