I am downloading full fedora 10 dvd. my question is that should i download live dvd/cd and upgrade from there or should i download full installation media dvd?

Which will save my time? The mirrors are pretty slow which is understandable. please advice.

I would recommend always doing the full download then install from that. This will mean you'll have the install media already in the event you have to reinstall later for some reason and not have to redownload everything. You can also later use this as a rescue media.

I would advise the other way around. IF you download the DVD and have to reinstall (for whatever reason, say two months down the line) you will have to download all the updates anyway (and there are a lot of update with Fedora every week). Also the DVD has tons of software that you will probably never use. Why download something you will not use. The speed on the mirrors will increase over time. Currently EVERYBODY is either downloading F10 or downloading F10 updates, so the mirrors are hammered. As the weeks go on fewer and fewer people will be downloading F10 and the update downloads will be spread out more evenly

I would also recommend the livecd. Apart from the small download size, the installation is much faster and less bloated. 2.17GB only and it lasted for a few minutes! After that you can easily install whichever package you want through packagekit.

After installing it check the Fedora 10 Post-Installation Guide to learn how to configure your system e.g. codecs, video drivers, additional applications etc.