Kinda depends...
If you just want an LCD screen, then just hook up a computer. Any desktop/laptop from the past couple years can play back video smoothly - have decent CPU, GPU, and RAM...and USB of course.
To loop the video, pretty sure you could just setup a playlist in Windows Media Player set to 'repeat'.
If you want it more complicated, like a video, then an informational screen that could be changed 'from the back', then another video, etc...then maybe you want to look at a custom application (which I could help you with).
Alternatively, you may want a finished/refined kiosk, which sure looks nice (like the scala link mentioned) but are pricey.
Here are two I've worked with before. Not cheap, but worth a look and pricing. The first is a smaller shop/better deals/good service:
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www.pearlson.com»
www.kis-kiosk.comThose will still have a computer under-the-hood, you're really just buying a pretty console and support. Still need a way to present the information...but maybe a straight series of videos and still images via a playlist will work for you.
KM