We went in Jan. for our 10th Ann. and I had many surprises for DH since he didn't believe me that Disney could be adult/romantic. Illuminations cruise, two rounds of golf, YSH then onto Jellyrolls, etc.
Looking back the most memorable parts to us were the unplanned and basically free things. GF gave us champagne to celebrate anniv. On our last night we picked up chocolate cake at MK then went back to our room got the champagne and went out back and sat in the dark overlooking the lagoon. We watched the fireworks then the water pageant. It was magical and romantic.
It was so unbelievably cold the whole trip and of course we weren't prepared for it. We spent endless hours cuddling like we did when we just started dating. It's funny how what appears to be a lousy situation turns out so wonderful.
Moral of the story - along with all the expensive things, don't forget to find downtime for just the two of you.