Backup Solution

We have (5) Windows 2003 Servers and need a good backup solution that one person can handle managing nightly.  We are currently performing a full tape backup on (20) 100GB LTO1 tapes nightly.  Should we consider some kind of incremental solution with the tapes we have?  How can we backup each server OS/data for recovery over a period of 2 days for the first full backup?  Since it takes so long to backup to tape (ie: 6 hours for 100GB) if the first full backup would have to be done over 2 nights... would this be a reliable backup for a disaster recovery restore?  Obviously I want to backup active directory, software, settings etc...

Our server setup is:
1-domain controller (5GB)
1-file/print server (70GB)
1-Exchange 2003 Enterprise (85GB)
1-Blackberry Enterprise 4 (5GB)
1-Web/SQL server (35GB)

All on the same domain.  Currently we are running Veritas BackupExec 10.

We were able to get full backups nightly, but have grown and are pushing 80GB mail, 60GB file data now.  We are performing full backups on Exchange Information Store and File Data.

I need to setup something that can be managed nightly (ie: no robot) that will enable us to backup EVERYTHING.  This includes a disaster recovery plan for server OS (system state, etc...) for any kind of failure (nothing in place now ... SCARY)

It is not neccessary to archive any data... basically we need only for disaster recovery.  Plans in the future for data archiving, but not now.  

Any solutions will be helpful... I'm looking for the best (easiest to manage, lowest cost) solution.  I am possibly interested in any kind of hard disk backup solution/tape combination etc...

Thanks in advance.