Per Dubious Quality;
SAMSUNG MCBQE64G5MPP-03A00 2.5" 64GB IDE Internal Solid state disk (SSD)
This isn't in stock yet at Newegg, but it shows an ETA of 9/06, and I think it marks the beginning of an era. Not for the price--$1299--which is obscene, but it's an SSD with enough capacity to be used as a primary drive.
Highly dependent on the user and their storage needs, obviously.
Five years from now, when most of us have SSD drives, this will have been a notable moment.
It's a little pricey, but so were USB drives a few years ago.