+1 to justforkix.
if you want to treat your family, go right ahead and get a good 3 TV. 90% of the time you will be watching 2D content only. the occasional 3D movies would be an experience the kids would love.most 3D movies broadcast on TV are kids movies anyway.
after a few months of watching 3D movies, if you like the experience you can think about adding a 3D blu ray player.
one thing to remember though is to get the maximum size TV possible to really enjoy 3D.