VT,
I'll second SD's and FOR's suggestion. Don't mess around with DVDs, buy an external disk and make a bootable clone.
My wife's computer had a hard disk failure last year, but because of a bootable clone, she was able to keep working, after I had taken the failed disk out and sent it away for a warranty replacement.
I'm not familiar with Acronis - I use Super Duper on a Mac - but the key with these programs is to set them up to do an incremental backup every night. After the first backup (of all the files), which might take a few hours, the nightly backups are quick and each morning, you will have a complete, bootable copy of your whole disk.
These disks are becoming amazingly cheap. The other day, I bought a Windows/Mac compatible 1TB USB 3 disk from my local Apple store for C$82 ( ~£40).
It is more expensive in the UK, but still good value:
G-Technology G-DRIVE Mobile USB 3.0 1 TB External Drive - Special Edition £59.95
You can setup the disk to have two logical partitions - one matching the size of your hard drive for backups and the other for storing other files.
It will be well worth the investment to avoid the pain and time taken to rebuild a working system from a DVD backup.