This is the older show, but it's a goodie! This is the pilot of Battlestar Galactica, from 1976 - you can get it for £7.89 from sendit and the cheapest I can see elsewhere is about £11. I'm a bit young to rememeber this show well, I just remember Face from the A-Team being in it. :)
Details: The original pilot movie of the cult sci-fi series. Far in the future, the twelve colonies of man are destroyed after a 1,000-year war with the evil Cylon Empire, a race of sinister cyborgs. As the sole survivors of the colonies, it is up to the crew of Battlestar Galactica to gather up the few remaining humans and help them to re-build their lives as they search for a place of safety - the mythical planet Earth. Starring Richard Hatch, Lorne Green, Jane Seymore, and Dirk Benedict.