We prefer aisle + window. You face each other instead of strangers when the divider is down (nice for a conversation, too), and only one of you has to climb over someone else. The argument for the middle pair is that you have more privacy (aisles are very open).

Keep in mind that unless you are Oneworld Sapphire (i.e. AA Platinum, BA Silver), you have to pay for seat assignments up until online check-in. Yes, even business class. So you might just wait it out and see what's available at T-24, otherwise your "free" (points redemption) flight costs you ~$150/person/direction in seat fees on top of the ~$500 in surcharges on the award flight.