I am a ubuntu user but I want to go to the next level to use debian because what I heard of it, but I get confused to what to install on my computer do I install debian testing or debain stable with testing repositories.

- I want to use this system to the home use only.
- I want to use the newest packages because the stable packages is too old to use.
- What about using more than one repository i.e stable with testing with unstable at the same time (the same sourcelist)
- Is the testing and unstable sid packages good enough for the home use?

Do not mix stable and testing, they get too far apart. Much better to run straight testing for a desktop machine, or to mix testing and unstable. Personally I run straight testing until I know I want something from unstable. Unstable is usually pretty stable, but it is named Sid for a reason.

You can get a Testing install CD at http://cdimage.debian.org/cdimage/weekly-builds/ . Alternately, you can install Stable, change your sources.list, and immediately upgrade to testing.

I have been running unstable (sid) with minimal if any problems that i could not resolve with ease....

and what about the experimental packages what is the best way to install them? to put the experimental repos or what I can do with them?

You don't want to run experimental, that's where things are actually broken.

Debian User Forums :: View topic - Howto: Set up and Maintain a Mixed Testing/Unstable System
http://forums.debian.net/viewtopic.php?t=15612