The cheaper NSXs are the 3.0 and auto (and usually in Red). Performance isn't the best (7+ secs 0-60), but they still do look the part. No rust issues either.
The R32 GTR would be nice, expensive to maintain, but you do get the performance bonus. But as you say, getting long in the tooth. Non GTR versions are comon as hell, and typically thrashed.
Classic sports cars like the 911 are not that bad, the air cooled ones are fairly reliable. Have a look a the clasifieds on PistonHeads.com (Just don't mention yuo like Replica watches, they'll tear you apart). They are a lot better than the classic Italian (Alfa, Ferrari, Fiat) equiv.
It's easy to suggest stuff when it's not my money
Of the moderns, the latest Mondeo got rave reviews (I'm personally not a Ford person). And the New Jag XJ (I think) is also nice. The bad BMW rep seems to be rubbing off onto Audi and Merc now.
Merc had build issues about 5 years ago .. quality dropped.
The Vaux Omega (now Signum?) was big and option packed, big depreciation though. The older deisel lumps were BWM sourced I believe.