It's more interesting to me to compare cost/GB on the most frequently shipped or bought capacity for each media. At 250GB, the SSD is at close to (or maybe just ahead of) the most common size. 250GB HDDs are basically close to EOL which I imagine can skew the 'sweet spot' price up or down depending on the situation. Under that definition, SSD sweet spots are probably 128 or 256GB, and HDD is probably 1TB or 2TB?

The cheapest 250GB HDD isn't really a good measure - twice the capacity is what, $3-4 more?

But is the 250 GB HDD still in production? I'm guessing that's a fire sale price. I don't think drives still in production ever go below $50.