New photo hard drive, quiet or fast?

I take several thousand photos every year with my DSLR (10MP), 90% of the photos I take are RAW (NEF) and I think it would be a good idea for me to have a dedicated photo hard drive, both for the extra hard disk space, and so that I don’t have to worry about back up.

I have looked around on the internet and have concluded that I don’t really need an external hard drive, and the internal ones are much cheaper anyway. So cheap in fact, I think it would be my best bet for me to get #2 1TB hard drives in a RAID 1 configuration that way I will have all the storage I will need for the next 10 years, and I won’t have to worry about backing up my photos all the time.

I currently have a Western Digital hard drive, and would like to buy another one. I have narrowed it down to the WD Caviar Black or the WD Caviar Green , my current computer is kind of noisy as it is, and I don’t want to add any unnecessary noise.

My question is: how much does photo work depend on a fast hard drive? I will be doing most of my work in Lightroom and Photoshop, and I don’t think ether uses the hard drive much after it loads the photo. I would prefer to have the quieter hard drive, but I am ok to settle with the faster one if you think it would be a good idea.