Yeah, theoretically after their puppy shots, they shouldn't need routine vaccinations. You can titer them to make sure they still have the antibodies against the diseases they were vaccinated against. You will still have to do rabies shots because that's required by the state unless your state is intelligent and lets you titer for those too. I'd say, as RFD said, an annual heartworm test is really all that should be needed for any dog (but I live in NV and we have pretty much no heartworm here, despite what the money-grubbing vets would like us to think so I don't really bother with that either).
I agree that annual vaccines are not needed. Over-vaccination, actually, can contribute to many issues, including allergies and other immune problems.
Rabies as required by law and that's it. I do have titers run every few years and honestly, if I didn't have fosters coming through my doors frequently, I wouldn't bother with titers at all - go ahead, ask me why.
Heartworm annually, tick titers annually, and that's about it for my two.