Let's take a look at the scanner choices for a few different situations...

A "Snapshooter" wanting web page photos and E-Mail photos from their prints. In this case, I would recommend a consumer-level flatbed in the $75-$200 range.  You'll be able to scan prints well enough for web use, e-mail, and somewhat basic reprints.  However, you've already lost one generation of information, in the negative-to-print process, and you are using a lower-quality scanner, so don't expect perfection!  Page five of my HP/Nikon scanner comparison shows a slide and print scan side-by-side.

A Hobbyist looking for good 35mm scans for web use and prints (that won't break the bank...).  In this case, I'd recommend getting a good, low-end dedicated film scanner.  You'll probably get an optical density rating of 3.0 or so, and 24- to 36-bit color.  2400 dpi resolution ensures enough data for printing and cropping.   You'll get great quality on well lit scenes, but some noise and detail loss in slide shadows (or bright areas from negatives).  You can alway send that special, dark, prize-winning slide out for a professional scan when you really need it.  The new HP Photosmart S20 is a good candidate here at $440.  The HP is unique in that it has a built in 5"x7" print scanner.  Note, however, that its print scanner won't scan transparencies or negatives!

A Serious 35mm Amateur Photographer or Photo Lab.  I would move up to a scanner with a 3.4-3.6 density range, 36-bit color, and 2700-4000 dpi resolution.  Here are some candidates:

Nikon LS-2000 - 3.6 OD; 2700 dpi; 36-bit; $1,550 mail order. I've had some mechanical problems with mine.  I liken it to an old Ferrari; absolutely great when it's running properly, but a pain much of the time!
Polaroid Sprintscan 4000 - 3.4 OD; 4000 dpi; 36-bit; $1,725.  A new model.  Haven't seen the output myself...
Minolta Dimage Scan Speed - 3.6 OD; 2820 dpi; 36-bit; $850.  The price is right...

A Serious Medium Format Photographer.  This is a tricky one.  I use the 600 dpi Microtek Scanmaker 4 with "glassless" transparency adapter (3.4 OD; 600 dpi; 36-bit; $650 incl. adapter).    This scanner has a glass-free lightpath for clean scans of transparent media, and comes with 35mm, 6cm, and 4"x5" templates.  8"x10" transparencies are placed on a glass tray.  The LF photos on my Cape Cod page were scanned with a Scanmaker 4.   This scanner has beautiful color reproduction and good density characteristics.   It's great for MF web and e-mail scans, but doesn't have enough resolution for large MF prints.  At 240 dpi printer output, you will only get 5.5" x 5.5" inch prints from a 6cm x 6cm original.

The alternatives are much more expensive.  1000 dpi "glassless" flatbeds, such as the Scanmaker 5, are around $1,400.    Dedicated MF/LF scanners such as the Polaroid Sprintscan 45 Pro, and Nikon 45AF are $5,000 - $8,000!   One suggested alternative is the Umax Powerlook III, a 1200 dpi unit with glass in the lightpath, at around $1,000.  Some newsgroup contributors have said it does a solid job.

A Serious Large Format Photographer.  Unless you are a true professional LF photographer requiring high-density, publication-quality scans, I would go with either a 600 dpi or 1000/1200 dpi "glassless" flatbed.  I went with the 600 dpi Scanmaker 4 plus transparency adapter for $650.  My Cape Cod scans are good examples of 4" x 5" scans of Fuji Velvia and Polaroid Type 55 negatives.  At 240 dpi printer output, I can make 10" x 12" prints from a 4" x 5" chrome.  If you shoot MF as well, or want larger digital prints, go with a 1000 dpi model such as the Scanmaker 5.  Agfa sells mechanically similar (identical?) versions of both of these scanners.

If you are really picky, or really rich, or both, consider the Nikon and Polaroid LF scanners ($5,000-$8,000) or jump on up to a drum scanner at $12,000 up.   If I were a rich, successful LF pro, I would definitely consider these.   Unfortunately, I'm still trying to remember to close the shutter before I load film on my LF camera, so I have a long way to go...

I hope you find this comparison useful, and if you have any questions or suggestions, feel free to contact me at the e-mail link above!

Most prices used are Buy.Com mail order prices in effect in October 1999.