Don't worry, be happy!
As people said here before, if you want to worry less about losing large amounts of data, use redundancy in the form of extra disks to store parity data. Then you need something to control it all.
Hardware RAID used to be the choice, but costs were high for NVRAM to protect against data loss due to incomplete stripes being written during power loss. But as RAID systems use a proprietary format, you were trusting all your data to that vendor. Good luck! The argument for hardware RAID was due to (1) guarding against data loss due to incomplete stripes (power loss), and (2) as processor speeds were slow, the stripe calculations used a large percentage of processor power, so hardware RAID used a dedicated controller to take the load off the main processor.
Luckily that's all changed. Processors are cheap now and speeds are incredible, resulting in 90-something percent idle processors. ZFS says let's use some of that spare processor capacity and put it to good use for stripe/parity calculations. ZFS has the advantage of needing no extra hardware, unlike previous hardware RAID controllers. Also, as ZFS is software, free and open source, the format is not a proprietary black box. ZFS obviates the need for NVRAM by using copy-on-write and transactions, therefore avoiding inconsistent disk state due to power loss. When you create your storage array you can specify to have single-parity or double-parity to allow your storage to survive one or two drives failing, plus you can specify multiple hot spares to be used when drives fail. Using these levels of redundancy & hot spares, plus doing proper backups makes data loss extremely unlikely, even when you accept that drives WILL fail at some time.
Once ZFS, you never go back :)
I've written-up a load of stuff about ZFS and how to use it, and I've provided a load of links to Sun docs if you wish to discover more about this revolutionary file system that will make hardware RAID history:
The storage game has been cranked up a few notches and competitors are looking over their shoulder at ZFS -- just take a look at Net Apps.
And no, I don't work for Sun, I'm just a happy user of ZFS ;-)