I also wanted to ask if you can stack protoboards. I have seen where somewhere there was a card that you could hook up two protoboards at one time. But, can you stack a third one higher as long as you don't hook up to the same pins. I was just trying to visualize in my mind how it would look with all 54 inputs filled.
Yes, many of the shield accessory boards are designed to 'stack' on top of each other. However keeping track of which I/O pins are being used which shield and how much current each shield requires can limit this concept.
Lefty
I am looking forward to working with the arduino.
Thank EVERYONE for their replies. 
or look at ExtenderShield`s
http://www.liquidware.com/shop/show/DTX/DoubleTall+ExtenderShield
So I don't have to do this each post, Thank EVERYONE!
Peter, this was GREAT, Liquidware. I guess I will have to get a second job to buy all of these toys. My mouth is watering! 
Just a thought: it helps if you use meaningful subject lines for your questions! After all, nearly all the postings on this forum are questions about the Arduino. Tell us what makes your question special, in the subject line.