This worked for me:
I just worked with a Canon camera this weekend, and you need to sit down and make sure that you've got every setting correct before you start plugging things in. With Final Cut off, and no firewire cable plugged into the camera, switch it to VCR mode, so you can watch the tape with the controls on the camera. Then go into the menu, make sure that you're not set to down-convert to DV. Get out of the menu. Shut the camera off, plug in the firewire cable to both the camera and computer, and turn the camera back to VCR mode. Open up Final Cut, and go to Easy Setups > HDV > 1080P24 Firewire Basic (or whatever setting you used + firewire basic). This should be the correct setup, but it really depends on how you shot. Cmd-8 to open up the log and capture window, and you should be good to go.
I had to digitize from the Canon camera with Firewire Basic, but when laying back to tape, it wanted a standard firewire, not basic, but this could be because I laid back NTSC DV material.
If this doesn't work for you, post back and we can see where we have to go from there.