I current have a standard def miniDV but looking to upgrade to HD. I typically shoot 2-3 hours of video on vacation then edit down in iMovie. With SD a couple hours+ of video unedited seems to be close to 30GB and my 2.1Ghz MacBook Pro runs that just fine. I have 2 external drives, a 500GB FW800 and 250GB FW400 (not that it really matters). How much space does HD video take up compared to SD and is HD much more taxing on your processors than SD? Will my MBP with 3GB of ram edit ok or tank?