I now carry an A20 everywhere, and it gives pretty impressive detail and sharpness from its tiny 10.2MP CCD.

I've just been studying the new "Four Thirds" lens catalogue, where the manufactrers helpfully publish MTF graphs for all the featured lenses.

What is interesting is the different parameters and quality levels that the various manufactrers use. Olympus lenses are measured at 20 lpm and 60lpm levels. Sigma show apparently terrific graphs, until you realise they are measuring 10lpm and 30lpm levels.

I interpret the data as confirming what I have always maintained, that independent lenses are not as good as marque lenses.

So in the context of this thread, I would buy Pentax....

R discs are generally thought of as being more stable than RW.

Cleaning of old negs is a specialist area and I would research it first. Also, try the process you choose on an unimportant sample first.

There are cleaning solutions that will help remove mold. You could rewash and dry the negatives.

I always have stored negatives in archival sleeves and only clean them prior to use with a Pentax cleaning cloth (intended for lenses) or a blower brush. There are also electrostatic devices that make the dust fall off.

Spotting of images is a breeze with scanned negatives in Photoshop. Much easier than spotting prints!

I only buy high quality CD-R, never CD-RW, and that's at least a reasonable back-up. Not every CD will corrupt simultaneously, but one external HD could.

There is a limit to how far we can go and even keeping a negative is no guarantee. Just look at a 30 year old colour negative and see how permanent that was...

The most certain way to preserve an image for the very long term is an archivally processed black and white negative or print. Archivally processing is an arduous process and most work done does not even come close to that standard.

Also, when using even 1GB cards the contents will not fit on one CD for backup. On this basis, 512MB seems ideal to me.

Do you need to extend the wide angle end of your repertoire?

If so, how about the 14mm f2.8, or, if you can use another zoom instead, the more versatile 12-24mm f4?

The SMC Pentax-FAJ 75-300mm is a useful and respectable lens, especially at its current very low price.

And price, probably. The lens did exist, but only very fleetingly.

The Pentax 18-55mm and 50-200mm lenses would cover almost any photography you could imagine. The quality would be excellent and the controls would all work in the same way. Also, the filter size would be the same for both lenses, useful as you would only need to buy one size.

Your older lenses will work, some with restrictions, and I would hang on to them and give them a try. Those you find you no longer need could perhaps find a new home on eBay...

Have fun!