To me, this is a very interesting thread. Makes me think of what I'd do if in the same situation.
My favorite car is a '69 GTO. The only new car I've ever bought was a '69 RA3 4-speed GTO, and I loved it.
But, what would I buy now ? For me, or anybody else looking to own a GTO, I suppose the 1st thing to consider is exactly which year body style you like the best. For me, that happens to be a '69 1st, followed by a '65. But, opinions differ.
Since this car, nor one I'd buy, would have to be numbers matching, or anything even close, that opens up the options quite a bit. For example: I like the torque of a 455 or similar size Pontiac engine. Well, neither a '65 nor a '69 came with a 455 engine. But, in this case, that don't matter. You can buy either one today, with the bigger engine, if you don't require numbers matching or period correct. Or, you can buy one with a smaller engine & swap in a bigger engine, keeping the smaller one for possible future use or sale, with the car.
For me, price would be a big concern. Many, if not most nice real GTO's are, to me, WAY overpriced.
Therefore, I'd probably look for a Tempest or Lemans, rather than a real GTO. There are lots of real nice clones out there. Hey, I like many of the non-GTO A-bodies just fine. And, they can run & drive just as good, when properly equipped. I especially like the looks of the '71-'72 Lemans & T-37.
I also like the looks of the rear deck Judge wings, on the '69-'72 A-bodies. Some don't. Color is a big thing to me. Obviously, any car can be painted some other color. BUT, at today's prices, a good quality paint job can cost many thousands of dollars. So, color & paint quality has to be a consideration, when car shopping.
With all this in mind, if I had unlimited funds, I'd look for or have built a Black '69 Judge. Wouldn't have to be a real GTO, just a good clone. But I'd want a good 455+ engine, probably with Edelbrock alum D-port heads, an original 455HO alum intake, a correctly built 800 cfm Q-jet, & a 4-speed Muncie, with a Hurst shifter & T-handle. I'd want a good aftermarket 12-bolt rear, with 3.55 gears.
And, since I'd have unlimited funds, I'd also have a Silver '65 GTO clone, with the same engine, trans, & rear. And, since I love bracket racing, I'd have a Pontiac bracket car set up like I want it, plus a real nice dually truck & alum trailer. But hey, enuff(too much) about me.
Hope some of this will give you some idea to help you decide on what kind of Pontiac YOU want.
Just for kicks, it might help some of the guys here to know what your max budget is for this car. A $25k car & a $50k car can be worlds apart. And there are lots of GTO's advertised for well over $50k. But, in some cases, you'd be paying mostly for the numbers matching, and originality, which doesn't sound like what you're lookin for.
Anyhow, good luck. Hope you find a good deal on exactly the car you want !