The prices will be cheaper by then because the next generation of SSD's will be out - the Vertex V2 is rumoured to be 'just around the corner' and I believe it's major advance is to have built in RAID and hence much faster speeds, however we are already approaching saturation for the SATA 2 interface and so these new drives will prob be based around SATA 3 which should be able to support up to 750Mb/s transfer speeds.
So the upshot of all this, if true, is that for the next generation of SSD's you might need a new mobo.
There is also some talk of upcoming SSD product utilising PCIe sockets rather than the SATA bus, so they can take advantage of the huge bandwidth already on offer through that.
As always with high-end equipment, when do you take the plunge?