If i am using the ppa:kubuntu-ppa/backports ppa and the ppa:kubuntu-ppa, will there be any interference between the two? So in essence should i disable the ppa:kubuntu-ppa ppa?
The Kubuntu PPA contains point releases for KDE software - i.e. slightly newer packages that are intended to go into Ubuntu Updates eventually.
The Backports PPA contains very new packages that are often not extensively tested. Be prepared for breakages and other stuff that may not work correctly. However, its an excellent PPA to test the latest cutting edge software - at the time of writing this, it contains KDE 4.7 whilst the default Natty configuration is KDE 4.6.
The packages in the Backports PPA will be higher in number, so will take precedence over any similarly named packages in the Kubuntu PPA or in the standard repositories. So it is safe to run both in parallel.