they think that my windows NT backup is enough, even though it can't even back up open files 
Hmmm
Wrong backup software 
Backup software? Whats that then? Our Linux VM, unsurprisingly, uses tar, gzip, and ftp to backup the forum 
Ummm its that strange stuff NT uses
....which i think ClarCE is probably using.....if it carnt backup open files! Lots of different alternatives about as you suggest....but depends on what hes backing up....exchange servers? for example
My W2K3 server that hosts the VM that runs this place uses ARCserve, complete with Exchange agent. I do not use SQL agent, and back up all the SQL stuff a different way...
5 servers:
1 PDC (W2K Advanced Server)
1 File Print (W2K3 Server)
1 SQL 2003 (W2k3 Server)
1 NAS (W2K3 Appliance Server)
1 Exchange 2003 (W2K3 Server)
All backed up by NT backup - despite the many arguments I've had, they won't give me the money I need to implement a proper solution, I look forward to the day that it all goes wrong so I can say 'I told you so' although it'll still be my fault in their eyes I'm sure...
Management here are a bunch of numpties sadly. I've tried everyway I can think of under the sun to get them to give me a budget here, its a joke really - especially from a 16 million a year turn over company. We've just been bought out by another company, combined we're now looking at 30 million a year and I.T. for the group is going to fall under my control, so hopefully things will change - I have a few prequesits for them before I pick up those reigns...
Linking everything together and pushing the ERP application I've developed out accross the group is going to cost money, if it comes to it I'll be hiding a backup solution within that cost.