Have dear old Dad get a fast external drive (USB2.0 or firewire) for the video capture files - this way fragmentation and space issues won't affect the operation of your new machine.
The bigger the better as DVD-quality video can absorb several MB of space per second of video. (5 min segment = easily over 1 GB)
MPEG4 is a good choice for compression to keep the filesizes down.
cheers