I'll ignore the case---I'd read the reviews of it at Newegg to see if there were any glaring complaints.
If it were me and it isn't, I'd shave maybe 80 to 100 off that processor and use the saved money to buy an SSD of 64 to 80 GB. Put the OS and applications on the SSD. Put all data on the 160 GB hard drives that you already have.
I'd even cut back to 4 GB of RAM if necessary to get the SSD.
Such a system would be more responsive in day-to-day operation than the CPU/hard drive combination you have suggested.
To repeat: do you need Windows licenses or DVD drives?
CPUs in the Sandy Bridge/Ivy Bridge category are all quite strong--particularly those in the $200 area and up. I wouldn't worry about them becoming "underpowered" in the next five years.