Well SATA 2 hard drives have older technology and fabrication than the new SATA 3 for what ever that's worth. Multi core processors work better for programs that are written to use them.
Yea external hard drives are holding up to 5 TB now days with very fast reads and writes. if your worried run 2 as I do one internal and 1 external for back up only, my actual data is on a 1TB WD Black.
The SATA II and SATA IIIdiffer in the transfer speed. By SATA II is up to 300 MB/s, and bySATA III – twice as much, 600 MB/s. Usually, the two are backwardcompatible, but in the long run, if it's only for data, it shouldn'tbe that tangible.
Games and most programswould use up to four CPU cores, so unless you are using a very heavyand specific software that you know is more hardware-demanding, Idon't think you'll be needing more than a quad-core CPU.
About the back ups, myadvice would be a lot like Clintlgm's – using an external drive toregularly backup and also an online storage space/Cloud. RAID is notthat old as an option, RAID 1 makes mirroring so you'd always haveone copy of the same drive and data.
