I'm probably in the minority here, but I think they should have stated with Tennant.
Say what you want about him, he was a very popular Doctor. I think "cashing in" on him while he is still fresh in peoples minds would have been a good idea as he would have been a really big seller and a great start for the line in terms of sales and orders, putting them in a healthy position to carry on the line without dealing their "Ace" at the start. Smith is the current Doctor and as such is the one that will be in most peoples minds, the one they see on TV each week and the one most people will want. I think for that reason they should have held him back for a bit. The longer he plays the Doctor the more people will "get to know him" and the more they would want a figure.
I just think starting with Tennant then a classic era release (Baker please) before Smith would get more sales. Once completest have 3 Doctors you are on a role I think you could even even throw in some villians (Daleks) before Smith.
I am REALLY interested is seeing where this line goes though and come what may I want a Baker Doctor before it ends
Bob