From what i know, filters are used by pros where precise colour control is needed, eg photographing for a paint catalogue, or textile brochure. In film days, a photog gets a batch of professional slides, shoots a few roll, does the colour correction to get it exact, and sticks to the same filters for the rest of the batch of slides, under the exact lighting conditions.
i don't know how the same pro will do it with digital, but i'm pretty sure he will not be using auto-white balance. He might set the WB to something fixed, and then correct with filters, since his expertise is already there, or he might attempt to tweek his WB until it is 'just right' and use that.
For the 'on-the-street' shooter, the filters are pretty redundant. They cost a bomb, and, unless one already has them and enjoys using them, they are a royal pain to use, compared to just pressing a few buttons on the camera. Most photogs don't give a hoot about colour accuracy, unless it's way off. Digital files almost certainly have to be post-processed anyway. That said, i think one who has the background in using filters will still fare better at colour-correction when in front of the PC.
For BW, some prefer to 'get it right' in the camera the first time (with filters), while others prefer to meddle in software. BTW, part of the charm of BW photography is in the grain/texture of the BW film and the control over the process. i don't think there are (m)any hardcore BW who shoot digital (as a total replacement for BW). BW shooters care to comment?
