Question : Problem: backup solution

I have gone through a number of solutions for back-up however I feel I need to have my own solution from experts for the following current settings:
I have a windows 2003 server (standard edition)(machine is HP Proliant ML 150 G2 with 72 gb scsi hard disk) , 12 pcs ( 10 with win xp pro and 2 with win 2k sp4) which are connected to each other via a 24 port dlink swith of speed 100kbs.We have Sql Server 2000 running on the 2003 server and email / proxy server running on one of the 12 xp professional machines.
On each machine there is some amount of data like emails specific to the user of that particular machine + some ms office data (word files / excel files) which needs to be backed up---this is common for all xp machines .Apart from this common feature two of the machines have some unique data to be backed up like accounts data, and ms access data on another.
The 72 gb scsi hdd on the win 2003 server has 20 gb free at the moment. We have calculated that everyday we add approx 10 MB of data on the server, and the increase on other machines must be not more than another 10 mb so a total of not more than 20 mb per day. The SQL database needs to be backed up daily and the incremental data is included in the 20 mb per day data. i have learnt about dat drives (internal and external avialiable in India for approx 800 us $ for drive) and SLR-7 drives ( Tandberg internal approx 900 us$ for drive and 45 $ for a media of 20/40 gb). However I am confused. I need answers to following questions:
a) do i need such an expensive solution. If no then what is the alternative ? if yes then please suggest a good and current device and a software for backups.
b) since the backup is on lan an internal device is suitable ?
Please note:
a) once the 72 gb scsi hdd gets full on the server I need to archive date to the backup medium for future reference.
b) data needs to be stored for long span of time and is critical to the running of the business.
c) I do not know how important is the backup speed for me as the incremental data is only 20 mb per day. However I feel the need to have a complete backup of the server and 2 of the win xp machines ( by complete backup I mean in case of any harddisk  problem with the machine I should be able to restore the machine to its original status before the disaster).
d) a solution which meets my requirement and is not costly would be appreciated.
e) A software which supports the suggested hard ware would be required and would be great if comes bundled with the hardware.

Answer : Problem: backup solution

I am the IT manager for my company and we have tried several backup solutions using different tapes and drives etc... What we have settled on is this:

We purchased a 1TB NAS (Network Attached Storage) device for $899. This gives us pleanty of room to add backups etc...

We liked this device so much we purchased 2 more. The first one for daily backups the second for weekly backups and the 3rd for monthy backups. You will probably not need 3, 1 will probably do what you need it to do.

The only problem with these drives is that you cannot take the backups off site. Any good backup rotation has the data being rotated off site (like in a safety deposit box.)

If your data is important enough not to lose, price should not be too much of an issue. If you settle for something that will cost you $500 and later something happens and you find that you do not have the data backed up you would wish you spent more money to have reliable backups.