If you need more IOP, here is a list from fastest to slowest:
1) Fusion ioDrive - PCI-Express based SSD, $1000+ equal IOP to 5-Intel X25s, size ranges 80-320GB
2) SSD - Intel's X25 is the fastest Sata SSD
3) SAS - Seagate's 15k.7(brand new) 15k rpm SAS drive, 146-650GB, $300-$1200, fastest 15k rpm drive on the market; Seagate 15k.6, 146-450GB, $250-900, about 15% slower than 15k.7; Seagate Savvio 2.5" 15k rpm drive, 36-74GB slightly faster than 15k.6 for IOP but in 2.5" size, 4-2.5" drives take the same space as 1-3.5"(these are bigger than laptop 2.5" drives); Seagate ES.2 SAS & SATA, 250GB- 1TB, only 5-10% slower than Velociraptor in IOP and yet only 7200rpm, $75-180
4) SATA - Velociraptor
In terms of data security, SAS drives provide a far lower error rate than does Sata, which looks like something that possibly happened to you. Also, you would want to use Raid 1, 10, 5 or 6 for real data security. With all those mentioned, you can have a drive fail and lose NO data, and with Raid 10 and 6, you can lose 2 drives and still lose no data. And no downtime if a drive dies. SSD drives are very compelling but are not trusted yet by people who work with servers and need more IOP. They are still in their infancy and have some kinks that need worked out before they can be fully trusted with important data that needs to be available 24/7. Also, "Enterprise Class" drives are worth the money if the drives are running 24/7 because they are designed to do so, whereas desktop drives are not. The price premium for enterprise drives is not due to the warranty but due to better and more durable hardware.