A top of line slide and negative scanner, such as the model offered by Nikon, will cost close to $2000 US (although less expensive units are available). Such a device will yield images with a resolution of approximately 3000 x 2000 pixels and files which are up to 18 megabytes per image. However, in quantity, you can have your slides and negatives professionally scanned to the same resolution for less than $3 US per image.
Therefore, at the present time, for all but the most serious amateurs and professionals, we recommend sending your slides and negatives out for scanning onto a photo CD. This is more cost effective than purchasing your own slide/negative scanner, will yield the best results, and give you a permanent storage device in the form of a CD which will leave your hard drive uncluttered.
The quality of the images will be inferior to what you would get from images professionally scanned onto a photo CD, but given the quality of most ink jet printers, and especially for use on a computer monitor, the differences are negligible.
To archive your images, we suggest storing them in a compressed format, such as a .tif or .jpg file format, and creating a library of files on a removable media such as a zip disk. A zip drive will cost less than $200 (will plug into the printer port of your computer), and each disk will cost about $15. As the cost of rewritable CDROM drives and disks keeps falling, within a few years it will make sense to save your images at home on rewritable CD's.