Inspired by Scott, I also replaced the HD in my 744T with the Hitachi 80 GB drive - after all, if he needs it in his 722, I need it twice as much in my 744T! note that there are two small white plastic screws holding the IDE connector on - you can see them peeking out from under the pink foam insulation strip towards the right side of his image #2085 (the top one is more visible). The case screws were a bitch to get aligned and screwed back in - Scott mentioned the small metal tabs that fit into small slots on the bottom plate and help align the bottom plate, I also found it worked better to leave the two front screws until last. Just like he reported, when I powered the unit back up it was ready to format the new drive, which only took like 30 sec.
Steve