The D100 is a bird in the bush...nobody knows what the image quality will be compared to the D1. Any comparison of image quality is purely hypothetical. I hope the image quality is very high and the street price low. We'll see.
One significant disadvantage to going with just a digital body: battery management. Battery consumption is voracious for digital cameras and you have to be prepared to carry the power (batteries, battery packs, chargers) you need for your shooting. The task is made more difficult when you're traveling. Going digital for an 18-day trip in the Grand Canyon is a real puzzle when you try to figure out a battery budget. Solar chargers don't appear to be up to the task when a large portion of your day is spent being drenched in rapids. Even if there existed a digital camera that I would choose to use instead of film, I'd still carry a film body as a backup given the "current" state of power consumption.
Until there's a full 24x36 imaging chip, you'll have your wide angle lenses neutered by the multiplier (more appropriately called a "crop factor" by Phil at dpreview). My superwide 18-35 zoom becomes a pedestrian 27-52mm equivalent with the D100's 1.5x multiplier. 28mm is much farther from 18mm in terms of angle of view than 600mm is to 200mm. Whatever the advantages of digital, I can't get exactly what I want with a camera that crops my wide angle capability.
The "free film" concept suffers a bit when you consider the rapid depreciation of expensive DSLR bodies. The economics can be good if you're a pro shooting a lot and not very good if you're an amateur shooting infrequently. If the Canon D60 comes in just above $2000 US, the resale value of older DSLR bodies will be even lower than it already is now. On the plus side, as DSLR prices drop, a 50% hit in depreciation is easier to rationalize if you aren't a working professional.
Wet blanket mode off
I'm hoping that as the prices are made official for the newest DSLRs, I'll be able to snap up a nice used D1 or Fuji S1 and get an affordable, capable digital SLR to replace my Coolpix 990. If the investment is reasonable, a DSLR doesn't have to equal the performance of a film body to be worth the added capabilities.