Although I don't have 2 kids yet (I could well end up with this kind of age gap), I have a friend who has a 5 year age gap and for much the same as the above reasons it works really well.

Also, DH is 11 years older than his sister (!) and although you find that big during childhood, now that they're adults it isn't huge and they get along well.

Also, remember that your kids won't know it any other way (for example, you can't ask someone whether they'd prefer to have had a brother or sister closer or further apart in age, because they really don't know what that would have been like). You have to do what's best for your circumstances, and you won't begrudge the next baby anything when it comes at the "right" time.