Ok...so I guess we should ask a few other questions...
What is your budget?
I'll be honest...A part of me finds this thread ridiculous...Yet still...I bite.
First off...You could go with the roboard, but I would suggest you go with a FitPC...I had a roboard and found it incredibly frustrating.
I don't see why you couldn't go with something like the arbotix with an RX bridge coupled with the FitPC...The arbotix can control the movement of the servos while the computer does other stuff...I have a setup similar to that on my current humanoid who is 2 feet tall when standing completely upright...(Almost never happens.)
Andrew posted plans for a ~3foot tall PLM humanoid...I think it used EX-106s...~$500 a piece the PLM Design would be $8000 in the legs alone. You could probably get away with less in the arms, and unfortunately if you plan on getting up after falling down you are almost definitely going to need them. The Farrells had a humanoid that I think was over 2 feet tall...I think it used a gumstix for a controller, but didn't do much in the automated department that I know of...It could play baseball though. :-)
In anycase, Good luck with this...Please keep us posted. Start a thread and update it with pics and video so that we can say we knew you when...
OK...I guess that is enough.