Although discussions of this topic probably have some positive cardio-vascular benefit, they usually seem to swirl around the same drain. Constrained to the brevity imposed by the style of Web communication, we usually seem to ignore, or gloss over, the fact that there are numerous complex market and technological dynamics at play, each of which affects reality in a slightly different manner.
The F6: I haven't studied its specs in detail, but it does seem to have several improvements over the F5, such as improved metering. Whether those are sufficient to motivate an F5 owner to "upgrade" (actually, to create another level of backup camera) is probably an individual choice. But,
having that choice is probably a good thing. Personally, I'm sticking with my F5 (and F4s backup) for now.
Digi-frenzy: It seems to me that the ability to rapidly turn over camera models at the consumer and pro-sumer level has, in part, solved a revenue-stream problem for manufacturers selling into an already well-saturated market. Instead of getting to sell the person a new camera every 10, 15, or 20 years, they get to sell a new one every 12-18 months. Sometimes less. Duty cycles seem to have been substantially reduced with many of the pro-sumer models. Additionally, many of these cameras seem to suffer from the rush to market. Several cutting-edge Canon users I know have run into significant bugs that should have been resolved before the camera was released. I'd love to see Nikon or Canon come out with a high-end digital SLR that provided user-upgradeable sensors and user-replaceable feature modules. After all, it's just electronics and firmware. I'm not holding my breath, however.
At the professional level, I agree with Graeme - it's an uphill battle to get paid for post-production effort required by a digital workflow. With film, that work is done by a magazine's art department after scanning the film. If the magazine is successful in imposing a digital-or-nothing requirement, however, they succeed in shifting that expense to the photographer, who is often already working on thin, or non-existent margins. As a photographer, do I want to pay $9/hr to an E-6 lab tech, or $25-$35/hr for a Photoshop-wiz assistant? Hmmm. Let me think about that one.
That is not to say that digital workflow doesn't have its advantages in professional situations, of course. Quick turnaround in news situations, and immediate sign-off for catalog work are two good examples.