If you are shopping for a scanner , choose a USB one - if you have a USB port. The rest of your decision is up to your budget. If you don't have a USB port in your computer, it's time to add one or get a new computer. USB is fast and allows hot connections - connect and disconnect without powering down your system. USB is particularly useful for peripherals that you may switch between computers a lot.
Most people hate using the pointing device on a notebook for an extended period of time.
For graphics people, resolution is everything. The resolution of a traditional mouse or trackball becomes worse with time, as the tracking mechanism gets dirtier. Don't try to clean it next time. Go digital, young man. If you are planning to buy a camera, do give digital ones some thoughts - especially if you use the Internet a lot.