Who are you, my wife? Seriously though, that's an excellent question and one that I've given some thought to. Here are my 80's bikes in running state, along with what I consider them best for:

Trek 760 - on the large side, mile eater yet light and responsive. On the fence between a new bike or dressing this one out with the best of components and wheelset. Already brifterized and carries a modern wheelset - this is the bike that gives me pause for getting a high $ all rounder
Gitane TDF - 84. On the smaller to right side, and probably my fastest and lightest bike. I really like this thing, but it is a mutt component-wise. Great sprint bike.
Neither of the above two will go if I cash in chips to get something really special...

Others:
Trek 630 converted to a triple crank with friction bar ends. Sort of a spring or gravel bike, with pasela tg's on it. It is a nice bike to both look at and ride, but not if you're in a hurry.
Raleigh Wyoming with carbon fork, brifters, and compact crank - on the small side - I use this as my all weather trainer, and it sports lights in the early fall and spring.
Bianchi Rando - fenders on it, road triple, DT shifters, it is my all around bike for iffy weather. Very large for me, but it is comfy and has larger tires so my spring mile eater (the bike I ride most often when it's between 30 and 50 degrees)
Fuji touring series 4 - the bike I dream about taking an epic tour on. Rarely ridden. You could eat off it, it is so clean.
Peugeot competition 531 frame with simplex - a nice original bike - I ride it occasionally and intend to do full resto over the winter
Also have trek elance 400 and trek 412 - sort of my other bikes, often pitched to friends and relatives, nice bikes but they don't compare to the 630 or 760.

Some I've owned since new and other have followed me home. The 80's lives on at my place...

As for what's missing in all that, I would have to say that none of them save the 760 (and possibly the wyo) are the bikes I'd grab for a back to back century ride weekend. The 760 isn't a perfect fit, but it is OK. I've recently sold myself on compact cranks and would love a low maintenance bike that is also beautiful to look at and ride. I'm thinking I'm going to be getting (not sure when) an Anderson 953 and temporarily hijack the components from my raleigh wyo to build it up once acquired. I need to determine which bikes will be sold to fund. Thanks for putting up with my "dilemma"