You can lead a horse to water . . . . miniDv will give you the greatest flexibility between your two computers. Any of your listed choices will not work with iMovie HD6. Recording back to tape gives you a place to archive your movies. Hard drive cams can't archive anything because you need to clear it to use it again. If a hard drive cam fails, your video files are gone, whereas with tape, you might lose a couple of minutes if a tape is eaten. Tape will produce superior quality video because it is not a highly compressed format, as HDD is. You could buy a very high quality miniDV cam with the money you have. Check out the Panasonic GS-500 on B&H Photo's website.