As far as the body is concerned, the F90X is head-and-shoulders above the '60, even though its design is over 4 years old. However, I must say I'm surprised by the low price of $157 plus lens. Any decent used 90X would cost more than that. Is it possible that it may have more than just a scratch?
As for the Nikkor 75-300 f/4.5-5.6, it was the first AF Nikkor lens in this range, so it is definitely an old design. Performance is still OK, but compared with the latest offerings from Nikon in this range (the newer 70-300 f/4-5.6 ED, introduced in early 98), the old lens is heavier, bulkier, and not as sharp optically.
I'm not too familiar with the two Sigma lens, but the way that they were offered with the N60, I suspect they form part of a package when purchased new. The 28-80 is basically your run-of-the-mill "standard zoom" lens that come with almost every entry-level SLR these days -- which means OK performance but nothing to write home about. As for the 70-300, Sigma actually makes 2 versions of it -- a more expensive version with extra-low dispersion glass and a cheaper version without it. Do you know which one is being offered? If it is the cheaper 70-300, I suspect its performance might not match the older Nikkor 75-300.
The UV filter is basically a piece of optically-coated glass that screws onto the front of your lens. As its name implies, it filters out UV rays and therefore help to enhance sharpness of your pictures in many circumstances. Since it doesn't affect the color of the image, it often serve as a lens protector. If you happen to bump the front of your lens onto something hard, it's better to have a filter out front to take the hit. Replacing filters are much cheaper than replacing the front glass-element of your lens.
Anyway, if you are confident with the conditions of the 90X, then by all means go for it. Pocket the difference in price and bid for more lenses.