I'd agree with the Subaru Impreza, MX-5, and 75 inclusion.
The Impreza, I can really see becoming a classic, because of the fact that it suddenly brought Subaru into the limelight, with a very competitive, affordable, and well-made sports saloon, which just so happened to be rather exceptional on rallies! My reason for wanting one in the future is that my parents had two of them in the 90s, into the early 00s, and I remember just how cool they were regarded as being in the school playground.
MX-5s, I never understood until I drove one, and since then, I've been bowled over by just how much fun they are, for so little outlay, relatively speaking.
The 75 deserves to be a classic, as it's a genuinely good car, having run one for 12000 miles, which I've just bought back in the last week or two.
They ride exceptionally well compared to the vast majority of modern cars, they're very comfortable, they seem very rust resistant indeed, with the earliest cars being 14 years old now, and I've never seen one with any serious rust. There does seem to be a bit of an obsession with buying absolutely top of the range ones, with as many toys as possible, and then adding an awful lot more to them. Some 75s that I've seen are rather tackily modified with lots of fake plastic wood, and even more chrome. I think Rover got it right with the 75, for the first time in a while, and it's just a pity that they're under appreciated. Mine is a 2.0 V6 Club SE, which I thought was a good compromise of performance, economy, equipment, but without a lot of the silly extras that go wrong. You'll struggle to find many on owners club sites that haven't been modified, but mine, LPG conversion aside, is exactly as it left the factory, and will remain thus. The only really expensive job on a V6 is the three cambelt change, with waterpump, which is usually just under £500, and needs done every 6 years, or 90k miles, officially. The 1.8s get a bad rep, but diesels don't seem much more reliable. V6s have their foibles, but are pretty good, for the most part. If mine expires, it'll be replaced by another one, if I want a car for travelling long distances in total comfort. They're really just amazing value for money, if you buy well!