Well, SSD drives are finally starting to get where vendors promised they should be last autumn.
http://www.ewiz.com/query.php?categry=0 ... asterdrive
Super Talent 1.8 inch 120GB MasterDrive KX Micro-SATA Solid State Drive
* Sequential Read Rate: 120 MB/s (max)
* Sequential Write Rate: 40 MB/s (max)
Which looks pretty darned good if you compare with the 1.8" HD alternatives and I believe its just a matter of months before you see a 1.8" SSD that is both faster and bigger than the HD alternatives.
I believe there was promises from some vendors early last year that there would be 120GB SSDs around 600 USD in August/September last year, but we seem finally to get there. One year later than the vendors promised.
That in any case a cost reduction of some 50% in roughly a year, which is pretty good and I would not be surprised to see that accellerate as you got a whole bunch of new producers that has announced that they will enter this market this year, including Intel and some of the big memory producers.
If SSDs continue dropping in price like now, I suspect the SSD will be cheaper than the 1.8" HDD in less than 2 years as well.
If we look at the other extremes of the SSD market now, you have on the performance side, the fusion-io which plugs straight into a PCI-e slot and goes up to 360GB on a single card with 6-700MB/sec transfer rates (bloody expensive of course). This card cannot be bought yet I believe, but it does exists and indeed works. There are very real prototypes out there which I can guarantee works, although performance is not fully as promised yet, they are still faster than anything else except pure memory drives and then it must be a drive that does not use a traditional storage interface as none of those can compete on throughput and latency with PCIe
On the capacity side BitMicro say they can offer 1.6TB capacity in 3.5" with their Altima E-Disk, but I am actually not sure if they produce them or just say they will produce if someone orders. In any case, you already got a major vendor out there claiming that they can deliver SSDs with higher storage density than any available HDD today.
Look at the extremes that vendors already offer and consider that there are already far more SSD vendors (companies with products, or which have announced that they will make products) than HD vendors (which number is dropping) and it should be very likely that we will see a very competitive market in the near future.
I really think that once the big silicon producers throw themselves seriously into this fight, prices will start crashing down and value will increase as quickly (if not faster) as we have seen on the memory market the last few years.
I am not suprised if vendors can push out a 20 rpm reasonably soon if they really want. After all, 15k rpm technology is a quite old now and I would really expect that we are able to make materials that can push this up 30% by now. I would however think that it only keeps the performance HD business alive max 2-3 years more, so the question is... is it really worth developing.
I don't really think so myself, unless the technology is practically there and can be pushed out at hardly any cost.