Whether I can rip the movies to an SD card or if I have to use an external hard drive, is there a way to watch those movies on this tablet? Does the media player that comes with this tablet play movies?
As long as your SD card plugs into your computer somehow (either with a USB adapter or directly into a slot) you can rip movies onto an SD card. I generally rip/convert to mp4 on my laptop, then transfer the file to an SD card. I use DVD Catalyst software -- it's inexpensive and dead simple, and it has built in settings for the Excite.
Yes, you can watch movies from an SD card -- try MX Player, it will play pretty much anything you throw at it as long as it's not DRM'd.