By William Gallagher BBC News Online

The Day After Tomorrow presents a worrying future scenario

Global warming lurches the world into a series of breathtaking climatic changes with extraordinary special effects in the movie The Day After Tomorrow.

Consumers are offered a choice of two DVDs. A single-disc version for �15.99 comes with the film and commentaries that mean you can see the film without listening to the dialogue.

You'll want to do that. One day we'll get a disaster film that isn't just a parade of special effects shots.

Not today. And this is why you want the two-disc version at �24.99: it's full of extras exploring the great effects.

Since you can shop around and get the two-disc version for not very much more than the one-disc, it's definitely the better buy.

As well as the same commentaries, the two-disc set gives you about two hours of features, most about the film but some about the science behind it.

The Sweeney: Series 4

You remember John Thaw and Dennis Waterman, you remember "Get your trousers on, you're nicked," but do you remember comedy duo Morecambe and Wise?

TV classic The Sweeney was a gritty 1970s cop series

They guest star as themselves and are surprisingly good in the tough crime show's only surreal episode.

How they came to be in it is the subject of one of the set's very well chosen and comprehensive extras.

This is the final set of the show yet it contains more extras than many new films do: interviews, outtakes and many PDF documents about the series.