Which Western Digital Caviar HDD is more reliable for a long time back up storage?

Hardware Hub Storage
1

I'm planning to buy a new HDD for back up storage - music, images and program installers; I'll be using my 1tb 7200rpm 64mb Western Digital Caviar Blue mainly for installed games. Which Western Digital Caviar HDD variant will last longer for back up storage?

Black

Blue

Green

Red 

2

Reds are designed for Network Attached Storage, and Blacks are "premium" grade.

So, id go for Red for long term storage.  

3

Thanks for the reply!