boroda, you should have a look at
XBMC. It is supposed to be a complete HTPC interface (like Windows Media Center), but works quite well as a video player. Besides a gorgeous interface, it maintains a database of your video files and movies, scrapes information - fanart, cover images, actor information, etc. - from various internet databases. Some examples from my work PC:
A movie list:
Various seasons of Scrubs:
It also does music:
XBMC is not much of an organizer, tho; then again, you don't usually have thousands of video files on your harddisk, so organizing videos manually in Windows Explorer isn't that big of a deal. The only thing you need to bother with is to give your files good names - "Title (year)" for movies, and "Title 1x02" (where 1 is the series' season and 02 is the episode number), and there are tools to help with that. Everything else - the descriptions, plot, nice images and cover art was retrieved by XBMC without me doing so much as lifting a finger.