I would replace the server ONLY if by upgrading you would improve overall performance. If you upgrade to a new server, you would need to either copy all your data or clone the data, so you may as well add larger hard drives. Some RAIDs allow you to extend the RAID. Your situation is a great reason to have two RAIDs, a RAID1 for OS and a RAID5 for data. Then you can make the data drive larger quite easily. Even if you didn't use RAID, which would not be suggested, you could have two drives and EASILY copy the data from a small data drive to a very large data drive.
You left out one key peice information. 30% of 300GBs leaves you with 100GBs of space. 30% of 36GBs leaves you with 12GBs. Big difference.
However, here is the reality. Your PM program and billing data program which will be phased out do not sound as if they will get bigger. So, from what you are saying, the only thing getting bigger is your AC. Now forgetting the Imported Items, it would take years for a solo practice to take up even 1GB of space on a drive. Imported Items would grow as a more steady pace. Even so, we import probably 50 faxes a day and, after a year, only have 4GBs of data. So, space doesn't sound like an issue.
Bottom line. If you are only upgrading for more space OR if your IT person is saying, "Hey, we have to copy that data and redo the server anyway, may as well get a better server," then fine. Otherwise, copy your OS and data a few times -- many programs will allow you to image or clone your data, then add hard drives to your server or your RAID and copy back.
As to the backups, EVERYONE does it differently. If you have fifty people, then fifty people will do it differently. However, if you have 50 users, my guess is at least 40 won't back up adequately.
As to the backups in the office, you need at least two hard drives preferably more. You wouldn't use flash drives/thumb drives in the office. Think of tapes. You don't back up to a taper over and over. You back up to a Monday, Tuesday, Wednesday, etc. and then take home Friday and alternate, etc. So, why would one do multiple backups to the SAME drive? For your take home, a flash drive is fine; it is just so small as far as losing it. Works just as well.
I back up only my data once a month to an external drive and keep twelve backups for each month and then start over. One year seems sufficient, but you can do more.
Automated backups are the way to go. The weekly backup that you take home is manual so that is good. I also do separate backups of just the AC and billing folder daily. I use a script for that. I call that a modular backup. So, if something happens to my data, I have a quick backup ready. I just like to have automated AND a quick manual backup.
FYI: If you are using 2003, you will have VSS (Volume Shadow Copy). This automatically backs up certain shared folders as often as you like. This accomplishes two things: First, it insures that your backup will backup files that are in use. And, second, it gives you multiple backups of allowable folders. This is nice because it runs in the background as often as you wish.
