As far as i know, first will be the 200LR. The first expansion pack should be the -300 and then the -F (freighter) Version. But i guess their should be enough people wanting the "normal" 200/200er.
If this planes gonna be as good as the NGX, I have no doubt it's gonna be my favourite longhaule-plane...well beside your B744 V2 ;)
And I really think there are many people desperately wanting a 777-200 and 777-200er too ;)