One being they were built 'better'.
Partially true. I love the feel of old AIS Nikkors in the hand, but for instance I haven´t shot a single image with the AIS 24mm f/2.0 since getting the AF-S 24mm f/1.4G - it really is that much better except for size and price. As for the craftsmanship, I dare say the AF-S version is very rugged in build, at least it feels that way.
Against the plastic fantastic 18-55, 55-200 and 55-300 the older lenses win every time in craftsmanship, hands down. Then again, I find the non-decoupled focus ring found in many D series lenses a sign of lazy/bad design. And I am not a big fan of the optical characteristics of some/most older lenses - from any manufacturer.
That capital letter N on the lens barrel could be: 1) marketing BS 2) needed to correct problems with newer lower cost lens design. 3) greater profit snake oil. In other words newer gee wiz bang is sometimes just a cover for lower quality manufacturing and greater profit.
And in the case of the 50mm 1.4G and 50mm 1.8G you are at least partially correct.
Sorry I do not have that buy, sell in two years, buy newest one and repeat personality. I like to buy and keep for a long time.
We all have different needs and criteria for equipment. I like to know other people´s preferences, because I am just curious to know why others do the same things in a different way.
I like to keep the things that I find exciting enough to keep. I like to get the photos with the least amount of hassle in post-production, and in that regard, the 24mm f/1.4G has served me very well - delivers every time.
A lot of the time, I shoot in very dark places. I do like the D7000, except for the size (too small for my hands or something in the shape that makes my fingers ache - a thing that never happens with the D300S/D700/D3S). I sold the D300S, because I did not like the High ISO image quality beyond 800 - the only reason I kept the D7000 is that it is relatively cheap and currently the ultimate non-dwarf-size Nikon DX body for High ISO shooting.