voodoo, welcome to the forum! I'm not very familiar with measurement so I will suggest on hardware only:
1) Ardweeny + protoshield (this shield? http://www.solarbotics.com/products/52125/
I just looked at the design. I don't like it too much! Could be fragile. The microcontroller pins are soldered to male pins. I bet after many insertions the pins could get damaged. On a second thought, with the protoshield I found, it's way less of a problem if you seat it on the protoshield and don't disturb it.
2)Protoduino, chip is not included? Making it not that good of a deal for the price. I doubt there is a lot of support or users.
3)Boarduino seems pretty good from a reputable seller LadyAda. There should be no problem with support and customer base but there is no shield for it so going from breadboard to having an LCD buttons shield is not possible.
Well, my suggestion after the discussion would be 1). You will benefit the fact it has a shield that you can plug in an LCD buttons shield on top for final installation. There's screw holes too. Important. On the other hand, for easy of use, you should get an arduino UNO to prototype with and only work with the ardweeny when you're ready to move from breadboard to a project box.
[Self promoting alert] Here is my version of LCD buttons shield. I consider it the best with all the software and support:)http://liudr.wordpress.com/phi-2-shield/