A few things I should add to the VueScan information:
At least with my Coolscan LS 5000 and 9000 VueScan handles the dark areas a lot better than NikonScan. It exploits (correct word?) the Dmax of the scanner much better.
I considered to purchase an Imacon because of the trouble I had with Nikon scan and my slides. With VueScan now I get almost the same results as with an Imacon. When I say almost I mean that the Imacon scans are just a tad better in dark areas, but the dust and scratch removal of the Nikon is second to none.
I've just re-scanned several 35mm negatives I've shot last year. Geez, what a difference! It's a real time saver because the scans with VueScan require less post scan editing with i.e. LightZone, so the investment of some US$ 90 pays off very fast.
A very important point: you can use your serial number for an supported platform, that means with Windoze, Mac and Linux. Ever found a really professional scan software for Linux?

Now you have it. It works like a charm on Linux, because Linux is far better regarding memory management.
Maybe I should add a nice trick here: select the 'color' tab, and in the preview window right click your mouse on a gray area, and you'll have a perfect white balance for your image (the option automatically changes to 'manual'). Going back to 'white balance' just double click the preview area and compare the colors. Oh, you don't have a gray area in your image? OK, just buy a credit card size gray card and place it somewhere at the edge in your scene. You can remove it later with a retouching tool like clone or heal or whatever it's called.
Next trick: once you've scanned your image, the data will be kept in memory. That means you can modify the color, filter or resolution settings or crop as much as you want, hit the scan button again and - bingo - the image is saved with the new settings without a physical rescan! This is a real time saver.
Then there is the calibration option for any sort of film. For negatives just get an IT8 target from Wolf Faust, shoot your fist frame of each roll with it and calibrate your scanner with VueScan. Or buy an IT8 target for any slide film and calibrate your scanner. The results are stunning.
Just my two cents. I hope you don't mind my excitement...