I was not around in this forum when the extra hard drive thread was started so I will make some suggestions here. In my opinion there are several methods of backing up your movies and MP3s each with their own advantage and disadvantage, you need to take your choice:
1) Memory Cards: Pros - these are really small little suckers and can often sit on the tip of your finger - Cons: they are often expensive and not real high capacity, I belive the biggest one yet is 16gb;
2) USB drives: Pros - small and easy to cary around - cons - like the memory cards they are not real high capacity and the price per gigabyte is rather expensive.
3) CD/DVDs: Pros - chances are that you have a writter in your laptop already that can handle quite a bit of movies and MP3s - cons - if you have an extensive movie library they can make finding the correct disk somewhat of a challenge; imagine someone with fifty DVDs holding fifty different movies, it becomes a nightmare trying to keep track of what movie is on what disk.
4) Hard Drives: Pros - inexpensive when you consider the cost per gigabyte and quite high capacity and costs are constantly going down; cons - often take quite a while to get those platters moving.
5) Solid State Drives: Pros - fast to access, cons - expensive
How many movies are you talking about? A large number? Over 100, probably the external hard drive is your best bet (I have a pal with this many any he swears that without his hard drive he couldn't find anything). Between 50 and 100, again perhaps the hard drive is a better idea. Between three and fifty - maybe a library of DVDs is the most cost effective way since figuring out which movie is on which disk is not so bad here. Or perhaps one or two favorites - I had a pal that stuck his two favorite movies on a 16gb micro SDHC and brags that this little chip that is smaller than the tip of his finger has his two favorite movies on it.