Which one is better for my laptop fedora 10 or 9 , in the sense the most stable one ?

hello whacky_john_007. i would suggest that you go with fedora 10 as it is the current stable release of fedora.

but I heard that KDE on fedora 10's got some bug..??

KDE4 on Fedora 10 works fine for me. What is this bug you heard of?

now, that's a different story.
i think that fedora 10 uses KDE 4 and from what ive read, it's not yet as polished as KDE 3.5. haven't had a chance to use KDE 4 yet.

I would suggest the newest. If you want to take advantage of the Fedora OS and you do not have much experience with it, use the newest. If you run into a snag, just ask and you'll have all the help you need. The Fedora project usually does a turn around about every 6 months. Find the issues and report them - you might even find the fix for the issue - then your part of Fedora 12 or something. So use the newest because Fedora patches don't come out after a newer OS. It is always being developed, which, I think, is one of the better distros - of course Mandravia is really impressive, my opinion. But it is your preference.

Any one version of Fedora is only supported for thirteen months. One month after F11 is released (May?) support for F9 will be dropped. After that there will be no official updates of any kind(for F9).

Fedora KDE has amarok to play MP3 or not?
Does it autodetect CD and mount it?

yes it does autodetect cd's !!
and it has amarok ..
and this command
yum groupinstall sound-and-video will get all the codecs you need to play all the audio and video files

Can I install the live CD onto hard disk?

yes
sure can !

live CD contains less packages than DVD.
but sufficient for normal use?

Yes, depending on normal use. All of the packages are still available via yum (requires internet). So you can install anything that you are missing that way.

And, FYI, the KDE 4.2 release is, in my opinion, much better then the older 3.5 release.

live cd is more than enough for a normal user ... the dvd contains a lot of packages , of which many may go unused by a normal user