I've been planning on taking a 40" LCD with me overseas as well, considering that where I live,
TV's (and most electronics) cost up to 2x as much as in the states.
I'd recommend taking an LCD as they are much lighter than plasmas (sometimes twice as light)
A 40" should be just under 21kilograms (46.3lbs) which is the luggage limit for economy class (on Aeroflot, anyways).
And a 37" is about the dimentions of an average hardcase luggage.
Personally, I won't take the TV in it's original box (just the TV with the orther parts like stand and remote seperatly)
just in case the customs might claim I'm exporting a "product" and not a personal belonging.
If the luggage is overweight, you can always just pay a small fine, something like $50 for every 5 kilo's (11lbs) over. (again, may only apply to Aeroflot)
If you don't want to take it as luggage but send as mail, then I really have no idea... sorry.
Since I'm going to America regardless, I may as well pick up a TV while I'm there.