Yes the newest, least used computer in your house. The reason you want newest and least used computer is that there is a relationship between the iPad and iTunes on the computer. Yes, you can get software directly on the iPad, but the system was designed to make iTunes on your computer the main library for the iPad. You can move stuff back and forth, you can use it to update the software, you can use it to backup the iPad. Considering that the iPad will become a very important tool for your child or your children, you need to make sure you have a long-term strategy to maintain it. Why least used? Because you do want another activity like playing online games or downloading stuff say cause you to get a virus that wipes out our ipad backups.
In contrast, let’s say you decide to put iTunes on a older computer and it dies, you may lose everything like pictures, video, drawings even music that was created by your kids.
Another alternative local backup it iCloud.