I'll just piggyback onto this since I wasn't sure if this deserved a separate post of its own.. 4 gig Sandisk Ultra II CF for $50 at Circuit City, I believe that was no rebate as well. I don't know if that price is good everywhere though. I was sorely tempted, but I decided to wait, by the time Mousefest rolls around I expect there to be better deals. And in the mean time I just can't justify it, I've got more memory than I've ever used on any single vacation, I'm sure not going to use it all up in a day.
I got a 4gb ultra ii at circuit city a few months ago for $50 as well so it seems like a regular deal. The extreme is much faster than the ultra, but 99% of users including me, only notice the difference when offloading entire cards at a time. Just my $.02