I'd certainly reccomend buying Che part 1 & 2.
Amazing films, totally in spanish (It would be ruined if it was in English) and subtitled in english!
It's in two parts because it would be a 5/6 hour film otherwise!
Del Toro's performance of Che Guevara is sublime, the film is shot beautifully, and it expetly tells the tale of che's life through flash backs from che being questioned by the American government.
If you're interested in Che then you should also buy The Motorcycle diaries which is about Che Guevara travelling around south america as a teenager with a friend on a motorcycle, and looking after lepors in peru!
Here's a little more about the film The Motorcycle Diaries
http://www.imdb.com/title/tt0318462/synopsis