All this advice is great! When we first started talking about the "big day" there was no question we would do it at WDW. We have a trip set for this Nov/Dec, but it will be our last until we begin our planning visits. DF is definitely not a saver, but I quickly became one when I had to save up for our first trip to WDW, which was a birthday surprise for him. We're both still in school (and I am planning on law school), so that limits what we can save, but we've been together so long that neither of us minds waiting a little longer to make sure that we can afford what we truly want. Also, we have been talking about a "Plan B", which is a still-Disney-themed but more local event. By working out the details now, we'll be in a better position to make the big decisions and have a "big picture" mentality, without scrambling or (hopefully) being caught up in emotion.
ETA: One thing I learned from a friend is to keep a pictoral journal. I go through the different bridal magazines and sign up for catalogues, that way I can cut out anything I like and put it in the journal. By having a representation of what I want, I can then shop around for a reasonable price. For example, my dream dress costs $3000. If I can swing it, great, but if I not, I can always take the pic shopping with me and try to find something comparable but cheaper.