If the offer is as good as it sounds then go for it. I'd imagine with that kind of offer your employer would provide a relocation package, healthcare, etc. These could work out very expensive if you had to cover them yourself, particularly if you own your home.
mrsgrips raises good points about the wife – no doubt you understand the importance of a support network with a young family. If you're moving away from family and friends will you be happy to have to start from scratch?
I've lived abroad when I was single and other than missing family and friends I loved it but a family brings a whole different perspective to things.
That said, it's only two years so what's to lose? And despite what most folks say I think America is a great country, the people are generally very nice and the country itself is fantastic. Having spent lots of time in California, Colorado, and Massachussetts (sp?) with work I think the East coast is the nicest part.
Good luck whatever you decide.