The other issue is that there aren't many 5400 rpm drives out there with the sort of capacity that 7200 rpm drives offer. The biggest 5400 rpm drive I can find on
Ebay
is 120 GB, well under half the capacity of my existing drive. It seems that the 7200 rpm drives are pretty much the standard these days.
What disk drives are in use out there that are reliable and have a reasonablly large capacity?