I really don't remember why I saw Master and Commander in the theater, it isn't my type of movie at all, but I actually remember getting excited when Paul Bettany's character discovered a new creature. I think I liked it in part because they didn't make his character insane, incompatent, or completely oblivious (or any other device they use to make scientists interesting on screen.) Somehow most of the movies with science elements I've seen lately have involved the releasing a toxic plague/computer virus/energy source/... that will end the world as we know it.
I don't know how it translated to DVD though. It as a visually stunning movie (if I remember right), but the pace of it was slow.
I almost forgot one of my favorite guilty pleasure science movies of all time... Real Genius! School for uber-smart science geeks, lasers, using dry ice to fool soda machines, and rigging a guys braces to broadcast messages. It is too much fun.