For the past few years, SCSI interfaces were considered the standard for scanners. SCSI interfaces can connect up to seven devices to your computer, and many high-end computers have SCSI interfaces already installed. If you have one of those, a SCSI scanner is probably best. Be sure to check that the scanner you are considering is supported on standard SCSI interfaces. If you do get SCSI, you can use this interface to connect external hard drives and tape drives, too.
SCSI versions are more, but they are much faster and more reliable.
One of the problems with SCSI is that many new multimedia computers do not have it. If the idea of opening your computer makes you uncomfortable, consider a different interface or having a computer store install the SCSI card for you. One other consideration is that many multimedia PCs have very limited expansion capability, and you may have difficulty adding a SCSI adapter to them. SCSI interfaces can be very fast. Data transfer rates of 1.2 megabytes per second are common.