The best gift my wife could give me is time. We are both very busy with work, and I really look forward to time spent with just the two of us.
Now depending on budget, a fishing trip would be great for the both of you. You can hire a guide or go to a lodge. There are quite a few in the states that are nice and there are different places suitable for different budgets.
Personally, I'd love to take my wife to Brazil on one of my Amazon trips, but the fist sized bugs would drive her bananas.