At least one review on Amazon says it takes a long time to convert the AVCHD of the Canon HF10 (and, presumably, any other AVCHD-based camcorder) to a file format natively supported by iMovie.
I see on the Apple site it says
iMovie supports standard and high definition video, as well as the most popular formats, including DV, HDV, MPEG-2, MPEG-4 and even AVCHD.
So... I don't know what's the correct answer. Who has experience to tell me if there is a lengthy "importing" process with AVCHD files, and especially with the HF10? I would hope to use a standard SD card reader to read the SDHC cards...