The problem I have with the anti-crop crowd is the implicit condescension in their arguments. Russ throws around words like 'sloppy' and 'lazy', and the implication is that anybody who doesn't subscribe to his view on cropping is just "banging away and hoping you can find a picture later in Photoshop." While I respect Russ's opinion on many other things, I happen to think this sentiment is hogwash. There are plenty of valid reasons to crop in post, many of which have already been mentioned concerning aspect ratios, lack of 100% viewfinders, etc.
I'd also point out that arguments which hold for one's preferred genre or style of shooting don't necessarily apply to the more general case, and may in fact be completely invalid for some other types of photography.
As just one example, consider the situation where you have 24mm and 35mm lenses, but the composition you want is really something closer to 28mm. What do you do? If you say move, or "zoom with your feet", I would say "wrong answer". I won't argue whether or not zooming with your feet is a good approach to documentary/street photography; but as a landscape shooter I can tell you it often doesn't work for me. For a lot of the shots I take, precise selection of perspective (meaning, camera position) is key to the image. Moving forward to shoot an un-cropped 24mm shot, or backing up to use the 35mm, would result in substantially different images from what I would get by using the 24mm at my original location and cropping after the fact.
For landscape photography, even small changes in perspective can make or break an image; and I'm sure that's equally true for some other types of photography as well. So zooming with your feet just doesn't cut it. Sometimes, using a zoom lens might allow you to get your desired crop in-camera; but I often use the perspective controls on my T/S lenses, and I'm not going to give up that capability just so that I can say I got the crop right in-camera.