I think it depends on what you're looking for.
The early NSXs are desirable because the steering is completely manual for really unmatched road feel, and hence the larger steering wheel, which I found acceptable in size. They were also probably the rawest versions, compared to later versions which softened and blinged up the car for wider appeal. But for a mid-engined sports car with great feel and suspension tuning, you can't really beat an NSX. You can approach it these days for a lot more $$$ (eg. Porsche Cayman), but I don't think you can exceed it.
There are drawbacks such as the alignment that ate up soft tires, but always remember that the higher performance a car, the more expensive its maintenance will be. Having access to a good, experienced Honda mechanic is very desirable, as many things on an 15-year old, limited-production car can go wrong.
For me, an M3 is like an apple to the NSX's orange. The M3 is a sedan made sporty, while the NSX is a real sports car. The S2000 may not be a good substitute because it's a convertible, and many track schools do not allow convertibles without extensive safety modifications. Again, it depends on why you're getting the car.
--Andre