Will NAND Flash / Solid State Disk (SSD) will be the future for Database I/O systems? Actually SSD are still limited in size (64 GB) and expensive (EUR 30/GB) and thus cannot yet compete with SCSI or IDE disks. But they also have an advantage. They are fast! For some uses like databases the price per GB is not that relevant. Also most of the databases fit into one or two 64 GB disks (more than 90%).
When you really get an I/O bottleneck you should consider to choose SSD: