Scott,
Check out dpreview.com and robgalbraith.com. www.dpreview.com/reviews/canoneos40d/page23.asp
* Canon has less sensor noise at high ISO.
* Canon has more IS, image stabilized, lenses available.
* Canon has more of the big glass. Witness how many white lenses are on the cameras at sporting events.
* To be fair, most of the photographers at a weekend photo workshop I was just at were shooting with Nikon.
I would say avoid the Digital Camera lenses that can only be used on small sensor, 1.6x magnification, cameras, unless you really need a 10mm, 16mm actual, wide angle lens.
Watch the ads from the big electronic retailers. I just got a Canon 40D kit with the IS 28-135 lens for ~$1250 from Circuit City, $ off plus a 10% discount plus 12 months same as cash.
If you really want a compact camera for point and shoot cave photos then look at the Canon G9. It now has RAW mode, 4096 exposure levels vs. 256 exposure levels in JPEG (12 bit RAW vs 8 bit images for JPG). There are times when a 30D or a 40D is too much of a tank and it is really nice to have the G9 in a jacket pocket or cave pack. Also you can get the G9 converted to take visible, IR and UV photos, www.maxmax.com/powershot_g9.htm. According to their guy doing the conversions, the G9 is his recommended P&S to convert at this time. Although they will convert a number of P&S and DSLR models.
nigel
Do not meddle in the affairs of dragons because you are crunchy and taste good with Dinosaur barbecue sauce.
