I completely agree that for us, those prices are crazy.
I'll bet though that some sports photographers will have them in their equipment just as soon as they are available. I worked with some photographers at Wimbledon (the tennis tournament) last week, and most Canon guys were using 1Ds cameras, shooting about 3-4 fps in RAW mode. That equates to about 450 shots on a 6GB card, or just 150 returns of the ball. Okay, that's enough for an entire match.
However, if these guys use 512MB cards then they must either change cards every 12(ish) returns, or use lower resolution or JPEG mode. The consequences of missing a crucial moment of the game, or having sub-optimal image quality is more than outweighed by "mere" money (for the lucky few).
Of course not all sports photographers are in such a position, but it's horses-for-courses. One thing aircraft photographers tend to have a lot of is - time between aircraft - this can usefully be consumed with copying files to laptops, digital storage devices, etc.
It is interesting that the consumer storage market (CD-R / DVD-R, etc) isn't really keeping up with these CF card sizes. Again, the press photographers are okay with their huge Sun servers running several Terrabytes (TB) of storage capacity. For those at home with increasing GB
's of images to store, it won't be long before DVD-R's will start to look a little limited(!)