My husband and I are true romantics! I am the type A personality, plan it thoroughly and make sure you are in the right place and time for the magical moment.... my husband just enjoys it when it comes his way. So we go well together. He lets me plan to my heart's content and he goes along for the wonderful ride.
I agree w/ what a lot of your posters have said and won't repeat their suggestions for you. But there are definitely some great ones and I would research them a bit and choose what best suits you. I agree w/ a previous poster and I have gotten a lot of my ideas from "Fodor's Walt Disney World for Couples" by Rick and Gayle Perlmutter who can really find the romance in every resort, restaurant, moment at WDW. I buy their book every 2 to 3 yrs and see what's new in the romance dept.
Here are some things my husband and I have tried. The Illumination cruise is a wonderful experience but it is VERY hard to get a reservation. If you are staying at a Deluxe Hotel, call your concierge and he/she will enter the reservation room just before the phones start ringing and get you the ressie. I tried for 5 days and called before the opening time and hit the buttons w/o listening to the choices, and could not book it before they were already taken. So try w/ your concierge. You'll have better luck. Also w/ the cruises for that and w/ the MK fireworks cruises, you can schedule a dinner w/ a waiter and everything and have a delightful dinner out on the water while watching a fabulous show. But this is expensive. It's $300+ for just the cruise, dinner not included..... but it was WELL worth the price. And very romantic.
If that's a bit too much $, you can schedule dinner at the MK in the castle (as a previous poster mentioned) before the fireworks, at the EPCOT outdoor restaurants before the fireworks, or at the California Grill at the CR before the fireworks. This just adds to the ambience of your dinner and we try to have at least one fireworks dinner per vacation. The castle's windows light up entirely and sometimes you'll catch a glimpse of Cinderella strolling the balcony, the Illuminations look amazingly good from England or Mexico (but a tough ressie), and the California Grill's fireworks display is farther away, but you can walk out onto the rooftop for a better view, and they dim the lights and pipe in the music for your pleasure. And the food is great too.
You can also speak to your concierge for a more private dinner, like the cruise dinner. They will serve you dinner practically ANYWHERE your heart desires, such as on the beach at the Beach Club, on a balcony at the GF, by the pool at the WL... you get the idea. We haven't tried this yet, but heard stories that it's a marvelous choice.
Artwork and jewelry and the bricks are always a nice choice and would make any wife smile. I always pick up a cheap trinket when on vacation to remember our moments on that particular trip. We then display them around the house. While staying at the GF I picked up one of their watercolor prints downstairs in the gift shop and had it framed to commemorate our stay there. I still look at it and smile. My parents just gave to me one of the actual GF paintings they used to decorate the hotel for a Christmas gift this year. The hotel had just been refurbished and they sell some of the "old" decorations not being used or things from your room like lamps and such (though pricey). So if you have a favorite resort or if you are staying someplace really romantic, ask the concierge or guest services in locating some of these wonderful treasures.
Also your stay has a lot to do w/ the romance. You really can't go wrong w/ any of the resorts in Disney, but some of the resorts are extra special, such as the turret rooms in the GF are huge and circular and surrounded by windows (but they have no balcony) or (if she is a balcony person) the honeymoon suites which look over the MK castle and so you see the fireworks every night right from your balcony. I enjoy the concierge service seeing as I get coffee and goodies at all times of the day and it did add a touch of romance to our trip. Now I own at DVC because I have 2 little kids and the kitchen and washer and dryer and jacuzzi are romancing me now. But when I was kidless, concierge was the way to go. I am sure you have a room already seeing your countdown timer, but that gives you some ideas to romance her on the next trip.
This one is not Disney, but one of my favorites. If you have a car, or maybe a taxi, you can take her to Discovery Cove to swim w/ the dolphins across from Seaworld and owned by them too. You can call ahead of time and have the dolphin do something sweet for your wife. They'll play ball w/ the trainer and bring the ball up to a guest and on the ball it will say "Will you marry me?" You can have it say, "I love you!" or "Happy Anniversary Sweetheart!" or something to that nature. I LOVED my day there and if she likes that sort of thing, she may too. You swim w/ the dolphins, visit the bird santuary, snorkel w/ the fish and walk hand in hand in your bathing suits in the warm sun while exploring together. It's like visiting a Caribbean Island w/o the long airplane ride. A definite must see.
I've got 2 more ideas for you, then I will let you go. On Allears.net, I read that you can call some sort of service which will help you plan out all the details for you. I think the name was something like "Pixie Dust at your service" or something cute like that. I noticed mainly people will use it for proposals, but it will definitely come in handy if you are in a crunch for time and need a little pixie dust and help right away. I read about scavenger hunts where they would put notes in different locations to direct the person to the beach at the Y&B Club, and then find X marks the spot, start digging and find a treasure box w/ that piece of jewelry inside. Scavenger hunts always make me nervous, but it sounds nice and most people LOVE them. Another I read guided her to a wonderful little set table overlooking the lagoon at the Poly or under the wedding arch at the Y&B Club or something and they sat down for an incredibly romantic dinner together w/ only themselves and the server. You can give her that piece of jewelry there as well.
Lastly, you can go all out by calling the wedding coordinator for Disney to see if you can rent out the Cinderella's crystal carriage and tiny white horses for a stroll around the resorts, or you can rent out the characters in their top hats for a private meet and greet etc.... but I am sure these will be pricey.
If you need any numbers for any of these ideas I am sure I would be able to find them for you. That book, Allears website, and a concierge or guest services where you are staying are great places to start. Remember, guest services and the concierge don't always have the suggestions as to what you can do. They seemed clueless when I asked them about some of these, but if you tell them that is what you are doing, they will be able to implement it for you. So I would utilize them when you already decided what to do. Hope all this gives you some ideas (if not for this trip) for the next one. Every vacation to WDW can be a romantic one. Hope you have a romantic time!
I LOVE Tigger and DH knows this and that's why EVERY trip, he makes sure to take several pictures of me with Tigger. 
