I have read many such similar questions,but they don't satisfy my needs because they are outdated
now currently I have a desktop with Ubuntu 12.10 installed on it.I would be using this desktop for few more months.
I have already installed a lot of software on this pc.Soon,when I would be getting a new laptop,I wish to install Ubuntu from a personalized CD/ pen drive so that I won't have to waste a lot of data usage and time on re downloading the softwares.
also I wish to make some changes in the core structure itself(because it's easy,i think). remastersys was a good option,but now it dead.
i would use a .iso file or the installation itself to do this job.