Which video format takes the least amount of space on harddisk

Hiya Harsh...
I think I'm right in saying there is not a lot to choose between a handfull of formats (mp4, avi, divx.. etc),
But I wouldn't hesitate in recommending DIVX.

It uses approx 700mb for a full length movie & is easy to accurately convert & burn onto a dvd disc.
I hope this helps you,
;) Slim;)

Real media files take about 300mb for a movie, rmvb format.
Other formats take about 700mb for a movie, like avi format

seahwk83,
When you say "real media files" is that in the same context as 'real media player' ??

Yes, rmvb can be played in Real Player but windows media player does not play rmvb

Here is a link that you can download a free player for rmvb files
Rmvb player download