Now that the effectively-$20 barrier has been broken, how low will they plunge? Will we see $15.99 for some? $14.99? For a 120GB? At what point, will they simply phase them out, like 8GB flash drives these days? I think that point is close, but with one caveat. There are older (BIOS) desktop PCs, that are limited to less than 128GB worth of HDD, either via BIOS or OS limitations. For them, the 120/128GB sizes are more-or-less perfect. (Using a SATA-to-IDE converter, perhaps.) For that reason, they might linger longer.
But there's no excuse for building budget rigs, and not throwing in a 120GB SSD for an OS drive, at least for browser boxes.
I look forward to "the plunge".
(Next up, 240/256GB SATA SSDs, for less than $29.99? Do I hear $28.99, then $26.99, then $25.99, then $24.99?)