seagate barracuda's all the way....
dont touch anything else... from personal experience
Yes the barracudua's are good drives, but they are also expensive and relatively power hungry.
This is why you can use other drives, and BACK UP.
I can't emphasise how important to people it is to back your stuff up. Sadly, it takes one catastrophic failure for most people to realise what they need to do.
End of the day, with hard drive prices as cheap as 5p/gigabyte, how anyone can afford NOT to back up is beyond me.
Companies with fibre channel SAN storage costing in the region of £7.5k per terabyte per year still think NOTHING of doubling that (so £15k a terabyte - vs £100 for 1 terabyte + backup for consumer drives) IN ADDITION to a daily backup system (again backing up onto fairly expensive hard disks / tape)... if your photos are earning you ANY money, and even if not, but you value your data and photos, you NEED to spend money ensuring that you won't lose everything.
Oh, and btw.. just a raid solution only protects you from hard drive failure. You should bear in mind that MOST data lossses are due to accidental deletion, filesystem corruption, malware, etc - this needs to be built into your backup plan too. Apple time machine is meant to be a pretty good system, personally I use a one way synchronisation using windows xp synctoy, meaning that deletions do not get copied to the backup location, which (very shortly) will be in a computer at the other end of the house, so even helping with fire protection too.
BACK UP!