In reply to Andrew W:
I ended buying at great expense, a Nikon 4000LS with an auto feeder. It produces very good results.
They are often on ebay, but rarely come up with the auto feeder as well.
I figured that I can do all my slides, then sell it on and still get a very good price for it. A sound investment.
I may even offer to scan slides for others and make a bit of money that way.
The auto feeder doesn't work well with old cardboard slides but is quite efficient with plastic mounts. Card ones need to be scanned individually.
The scanner will also do negatives.
Don't be tempted into one of the lesser Nikon scanners as there may be connectivity issues … non USB / non Firewire etc.
The Nikpn software is also an issue with modern PC / Mac. I bought Vuescan and it does the job excellently.
Good luck!