Is it better to setup a RAID array or a batch copy command on a scheduler? My needs are simple - to backup my important files (some source code, financial data, etc.) on my home network nightly to a separate hard drive. My server OS is Windows Server 2008.
RAID is not meant to be a replacement for backups. It's a method for making your harddisks redundant. If one disk is failing, the information will still be available on the partition.
But let's say you accidentally delete files or the folders on the RAID partition. In this case the deleted data will not be available on the other disks of the array.
So, if you're using RAID, I strongly recommend doing regular backups to other media (NAS, other servers' shares, tape etc.)
Another option-- you can purchase an external USB Hard drive from any BestBuy or Walmart. Plug it in, run your batch file to copy the important files, then unplug it. That'll give you protection from virus/computer corruption/lightning strike. They're cheap and it works well.
You might also consider some of the free online backups like Mozy or Carbonite so that your data is protected even in the event of a disaster at your home.