I'm probably being over-fussy, but it's partly a question of tidiness and partly related to hardware. For a number of reasons, I prefer to store videos as 720p mkv files: my hardware handles them better, they take up a lot less storage than uncompressed 1080i and Matroska long ago replaced avi as the standard format in my collection. I never store anything long-term if it has adverts in it, hence my interest in VRD. Also, I'm not sure whether Humax-specific files will remain playable a few years on, whereas I'm fairly confident about mkv.