I went to an interesting discussion called "Big IT meets Big Web" today hosted by Battery Ventures which brought together a bunch of nerds to talk about the harmonic convergences of IT and Web worlds and deploying services in the cloud. One idea that struck me, was that many of these companies have huge data stores that are never erased. This means we have too many features in the magnetic disks and solid state drives we are using today: they do not need to be erasable/reprogrammable. The vast majority of data storage they need is "Write Once Read-Many" or WORM.
Crystal ball: in the near future, reprogrammable flash ROM will be replaced with write-once PROM. PROMs will be cheaper if designed as a write-once fuse array structures. A crossbar and fuse-array can be higher density than a floating gate flash ROM design. It may also require simpler processing steps--though the row decoder and sense amplifiers required for both types of storage may be the determining constrain in that regard.