M box 2 pro or Mbox 3 usb ?

[Rski]

Greetings all,
I need some advice. I have never used any form of software to record but i am making the transition and decided to go with pro tools . I am planning on buying through a third party ( everything is legit,Nothing stolen or shady. It's just friendlier on my budget). The choice is either the M box 2 pro w/ pt 7.4, which I thought to go with being I heard good things about this box(fire wire, little to no latency) and then just upgrade to pt 8 or the M box 3 -not pro just usb- but comes with pt 8. Which would you suggest I go with ? also my laptop runs on Windows 7 So wont that be a problem if i go w/ the pt 7.4 unit Then try to upgrade or cross grade( not sure if it's the same thing) to PT 8? Thanks. Would really appreciate some input.

[M-ManLA]

MBox Gen 3. Might as well be future proof.