Ports and interfaces: With storage, you have to make sure that the drive you buy is compatible with the system you wish to use it with. This is a crucial consideration if you're buying a solid-state drive or an internal hard drive, as a 6Gbps SATA connector won't help if you don't have 6Gbps SATA on your system. Unless you're the type of person who likes to tinker with your PC over time, system compatibility for an internal drive will never change.

On external drives, look for the fastest connector that your system can support. For PCs, that includes eSATA and USB 3.0--but only the latter can work without a power adapter. We recommend USB 3.0; even if you don't have USB 3.0 on your computer today, a USB 3.0 drive will work at USB 2.0 speeds when connected to a USB 2.0 port. Chances are good that you will have USB 3.0 ports on your next machine, so that drive should last you a long time. Related: