If you buy the N75, not only will all your lenses hold their value, but if you ever want to go digital Nikon sells the D70, which is a great DSLR. The only part of that setup that will lose value is the camera body.
Film cameras may eventually be a thing of the past, but SLR is here to stay. There is no such thing as a one-size-fits-all camera, and interchangable lenses are a must.