Agree with Ken. First, no matter what you hear about the dramatic floods and online backups and take homes, backups in your office are the best by far. You have your data right there, and it's fast. As Ken says, get some eSATA drives (6Gb/s), do two or three. I do five for every day of the week. Then take one home twice a week. Finally for good measure, do the offline. Remember, most offlines do not use VSS or open file. Many back up one file at a time so the whole database must be taken. You want byte by byte or even better, block backups.
One good way to do it is to have your main computer with OS and data, then have a 2TB drive in the computer and do an image every night using Image for Dos. This gives you a PERFECT image.
