Sorry, this cold weather brought on brain freeze and I misinterpreted your question. Firstly, the links I provided above will lead you to several free book reader software - and Calibre can lead you to even more. Most ebook readers are downloadable for free for reading books on one's computer - I have Kindle's, Palm's, and Mobipocket Reader (readable by Kindle, and probably vice versa). Epub, which is the book format for the Gutenberg project (thousands of downloadable free books) is available from Adobe Digital Editions
(easier than going to the Adobe.com site and trying to navigate through all options to find it). And some books and magazines are readable using Adobe Acrobat reader (.pdf format) - Scientific American is one, for example. New Scientist apparently uses Mobipocket so that can go onto the Kindle also.
Our Kindle has a 2 GB internal flash memory and supposedly can hold approximately 1500 non-illustrated books. That's a rather large quantity of books to keep track of.
My Palm phone has a mini flash card inserted, with 1 GB memory, and I use perhaps 10% of its capacity, removing books after I read them to keep the index easier to navigate. 4 GB and 8 GB SD cards are getting so cheap that it's worth using them for highly portable external storage.
Calibre's software indexes one's library by author, publisher, and format. The destination for these books can be on one's hard drive or an external drive. I don't store movies (yet) but this computer has a flash card slot so I could use that to save a huge library of books. Wonderfully portable storage, these SD and XD cards. Windows 7 can use an SD card as RAM to expand memory. One can double or triple memory for very little money this way. Since I have a USB card reader as well, I have lots of storage and memory options available.
Our new boat TV has a built-in DVD player, and also USB slot and card reader slot so we don't have so many DVDs lying around.
Boy, do I natter on. Hope this is helpful.
P.S. Do you have a PC on the boat, or just a laptop?