I own an 84 Fuji Club so I'm quite familiar with it, I also own a few other older bikes as well as a couple of new ones.
All the usual wear parts, like rear gears, chain, brake pads are all found at LBS's, major parts like a new derailleur of the same type on it now can be found on EBay with a few even brand new and unused. I changed mine over to a 7 speed without having to spread the rear stays.
Sure you can look at a new bike, but to get a bike of the quality of that Fuji you would have to spend a lot more money than you think and you still won't get the reliability! If the Fuji has been lubed and adjusted properly it will ride very nicely, and it's a steel frame adding to the ride quality you're not going to find with a new aluminum or carbon fiber bike.
My bike came with Suntour ARX, I've had other Suntour models and the ARX impressed me the least! So just last month I took out my new and unused Suntour Superbe stuff that I had since the late 80's and took off the front and rear derailleur off the Fuji and put on the Superbe derailleurs, I also took my Torelli Master Series wheels that were built with Suntour Superbe hubs off of my old 84 Trek 660 I used when I use to race, the rear wheel I had converted to 7 speed, and I put that stuff on the Fuji, and I had a new set of Superbe pedals and put those on the Fuji as well. I still have to remove the Superbe brakes and levers and get those transferred, then I have to put all the old Fuji stuff on the Trek and probably sell it at some point. I'll probably leave the old and high mileage Suntour Superbe derailleurs on the Trek when I sell it, I haven't decided yet to keep those and place the ARX crap on it, or forget it and keep the ARX for another project.
The old Trek had faded it's yellow decals to a faded white, and the paint is faded, all from intense S California sun for 20 years and over 150,000 miles. I was going to have it repainted, but I can't get paper transfers only vinyl transfer duplicates, and I didn't like the way those look, and repainting can get pricey as well, so I just figured it wasn't worth spending that kind of money on that Trek and then not be happy with vinyl transfers.
Anyway you would have to spend around $1,800 to get a bike equipped with Shimano 105 which is extremely reliable yet relatively low priced, and still not get the ride of steel that you have with the Fuji. Yes I know a new bike can be exciting, but will it satisfy you in the long run like your Fuji has been? no way, not even close. If you have a lot of money you could look at Titanium bikes, those actually ride better than steel and will last longer than any aluminum or carbon fiber bike, and much more resilient to crashes...well accept for the CF fork.
Now here's my story. I have an 85 Schwinn Le Tour Luxe that was in excellent condition with very little miles on it that I used for bike camping and later I was going to use it for touring, some idiot sideswiped me and in the process bent the fork to the point of no return. So I bought a new touring bike, a Masi Giramondo, yes it has all the newest stuff including disk brakes, but all the touring bikes I looked at are heavy, and so is this one, the Schwinn was only 26 pounds, the Masi is 35 pounds, howbeit when I get new tires for it I will cut that weight down by 4 1/2 pounds, the factory equipped tires are horribly heavy, but it will still be about 4 pounds heavier than the Schwinn. Both are steel, but the Masi uses larger tubing and thus doesn't ride as comfortable as the Schwinn did, some say that the Schwinn flexed too much under load, and that is true, which probably accounted for some of the comfort, but once I switched the original AL pannier rack to steel that flex went away but the comfort stayed the same. Anyway, the point is, I would have much rather kept the Schwinn had I not crashed it. There was only two minor changes I was going to do the Schwinn, and that was move the shifters from the down tube to the barends, and build up a 700c wheels for it instead of using the 27" wheels where finding tires that size could be difficult to find touring and having to go to a small shop someplace, everything else was good to tour on.