Switching to single on the withholding is great, especially if you both make good money. We have to withhold at single and each of us has an additional $600 withheld each month because of the marriage penalty and AMT.
The only point I would make is that upping the charitable contributions does lower your tax bill, but it's a net loss of income for you because your deduction is on cash that is out the door. So upping to $5000 will result in you taking home less money than if it was at $3500.
Other point is that you should look at the 529s -- aren't they usually state specific? Worth thinking about if you ever could conceive of moving.
529 doesn't help your federal tax bill. A lot of 529's have crappy plans (read:high fees). It may or may not be worth the deduction. They are state specific, but you can use for any education expense. Moving is not an issue. You can continue to contribute to the plan once you move, but may or may not get a STATE tax benefit. In fact, anyone can contribute to any state's plan. Utah is usually the plan most people go to. You can also open up a 529 in your own name. Personally, I'd hold it as cash or max out your IRA contributions until a child actually comes. Adopting can be a difficult process as well.
take advantage of the deductions you have, but don't go out trying to create them.
Do you and your husband each have an emergency fund with $30k each? If so, why?