I may have limited knowledge in this area (being a single guy and all), but I've been told I have this part down correctly.
NEVER buy something practical for your wife's (or girlfriend's) birthday or Christmas. It will only cause years of grief (they never, ever forget).
You need to get something impractical like jewelry, stuffed animals, fine candy, purses, shoes or a new Jaguar (or a stuffed animal wearing the jewelry while holding the candy next to a nice purse and shoes all in the front seat of a new car).
Of course, you've already started making the garage liveable, so you have a fall-back plan I guess...