Downloading high definition video from Canon HDV Camcorder to a Macintosh computer running OS X

The anwser here is true but very simplistic. The truth is that it depends on what kind of computer you are running (Imac, Powermac) and what software you are using. Imovie HD is awesome for easy capturing of HD and does a fine job on most computers, although slow editing on the older G5 but if you are doing a small or simple project Imovie HD should be fine.
FCP 5 works OK on a dual 1gig G4, better on a G5 and since the Universal release kicks butt on the Intel Macs.
Problem...FCP setup depends on the camera. Don't think you are going to start capturing and editing straight away after hooking up a HD Cam to a mac and firing up FCP 5. Default HD setting will most likely result in video and audio that ned to be rendered (that just sucks). Fire up FCP 5, make a new sequence, right-click (control-click for those with a one button mouse or do yourself a favor and buy a two button mouse today!) Go to settings in the contextual menu and change the frame size to 1440x1080 and use the Apple Intermediate Codec. You can do the same thing in the Audio/Video preferences under the Final Cut Pro menu item. You may have to do some tweeking as I have found unlike DV cameras that have been around long enough to become fairly universal HD models between different companies do not all respond the same. Most of all remember 1 hour of DV is approx 13gigs of space 1 hour of HD is approx 30gigs.