I have actually given this a lot of thought and I agree with Jerry here and predict that is exactly how it will work out. Syracuse will most likely end up in the Coastal Division with Boston College as its permanent crossover game while Pitt will end up in the Atlantic Disvision with Virginia Tech as its annual crossover game. That makes the most sense for everyone, IMHO.
For those who don't know the current setup, here it is (crossover game is listed in corresponding order):
Atlantic: Boston College, Clemson, Florida State, Maryland, NC State, Wake Forest
Coastal: Virginia Tech, Georgia Tech, Miami, Virginia, North Carolina, Duke
Remember, this is a classic zipper alignment with a team from each region basically being split up. By putting Syracuse in a division opposite Boston College, that would allow the ACC greater access to the valuable New York - New England corridor.
Also, for this to work best it is imperative for us each to establish or re-establish rivalries in our new league. For Pitt that's going to be pretty tough as we already have annual games against West Virginia and Notre Dame and people feel pretty strongly about both of those games. The only way that I see either of those games ceasing is if those teams decide that they no longer wish to play. And I'm not even talking about the now dormant Penn State game - the granddaddy of them all for most Pitt fans (and SU too I presume).
That means that Pitt needs to get Maryland and Virginia Tech on our home schedule every other year as Maryland is very similar to us in many ways and is just a short four hour drive from Pittsburgh. That could easily blossom into a rivalry. As for Virginia Tech, we have played some incredible games against them over the years and their fans always came to Pitt in droves. I suspect that would continue if we played each other every year.
For Syracuse, I suspect that renewing your game with Miami is extremely important to you and obviously so too is your now annual game against Boston College. Also, you would get the added "benefit" - if you can call it that - of regular home men's basketball games against Duke and North Carolina - many of which, I believe, will be played in MSG for territorial reasons. That is presuming that the ACC adopts divisions in men's basketball - which is not guaranteed.
As a Pitt fan, though I will miss the games against Miami, I actually believe that the Atlantic Division will be better for us in the long run as all of the schools on that side of the docket are good traveling fan bases and that is a big issue for us.
One word of caution about all of this. I have heard from a number of folks "in the know" that the Tobacco Road consortium have already begun pushing for a North/South split - apparently the current zipper alignment has not been kind to Duke's and Wake's football attendance - and if they get their way the Virginia schools would likely lose out in that scenario. That may be why the VA schools are being so pushy about this issue. Anyway, here is how it would likely look in a North/South split:
North: Boston College, Syracuse, Pitt, Maryland, Virginia, Virginia Tech, Miami
South: Florida State, Clemson, Georgia Tech, North Carolina, NC State, Duke, Wake Forest
I think they'll stick with the zipper arrangement and will only consider a radical overhaul if the league goes to 16 teams.