Sandisk announced a new line of SSDs on Jan 8 (thanks for the tip ZDnet!) that take a step closer to the tipping point where regular, spinning hard disks no longer make sense for some people. People for whom pure capacity per dollar is less of a priority vs. power consumption, reliability, or speed.
A 240GB G3 series SSD drive from Sandisk will sell for $499, and will come in either 1.8" or 2.5" versions. Its main advantage is speed - 200MBs read and 140MBs write speeds - about 4 times faster than those of a 7200rpm desktop drive.
Put 5 of these babies on a fast RAID0 controller, and there you have 1.2TB array with a theoretical bandwidth of 1GBs, for under $3K. While that may be still expensive, the kicker is that it is fast enough to pull two streams of 10-bit 1080/60p, which normally requires a stack of 20 desktop or server drives in an array requiring lots of power and cooling.
We are getting to a point where uncompressed HD editing can be done on a laptop in a Starbucks shop.