Professional advice is exactly what you want, so book a consultation with a travel agent.
Don't believe all the advertising you hear. It can be cheaper to get an air & accommodation package, but not always. Whenever your travel agent gives you a price, ask about any other available options. You might even contact WDW yourself and ask them if they have anything available.
My wife (a dedicated bargain hunter) did that very thing last year, and we ended up paying half what it would have cost us if we'd just booked the first 'special' package available. We actually did flight & accommodation separately, flew on a domestic flight (not so easy if you don't live next to the USA), and got an incredible discount at Disney World just by asking if one was available.
Your best bet financially is always the last minute sell-off, but there's a catch. You need to keep your schedule open so that you can pack up and leave on 48 hours' notice, and you have to take whatever is available. It'll be something good, but you won't know where you're staying until you get there.