Don't limit yourself to a gmt for the birth year watch imo, find any 66 Rolex and make that your birth year watch maybe. As for modern... it's a must for me personally to have one gen modern Rolex in my collection at any given time. I may swap it often or I may not, either way it's important for me to have something new and waterproof for those rainy days or when going for a swim etc. I don't see why you can't do the same, as long as you can afford it. If it's a case of one over the other I'd of course pick vintage.