Look at it this way: at 8 GB, you are already compressing the original content by at least 50%, and more like 75% for some titles, and hard drives are cheaper than they have ever been. If you must have smaller files, you can try two things: 1) reduce the video bitrate or frame size and/or 2) re-encode the audio to AAC instead of passing through the original 5.1 or 7.1 audio from the original disc. Both of these will reduce the quality to some degree, but it may not be too much and will depend on your personal tastes.
