Now for some explanations as to why SSD is the better choice. Currently the X-25 Intel and the OCZ Vertex SSD drives are very fast and very reliable. Just to be clear the OCZ Vertex are the best SSD's you can get on the market at this time. With Reads of 230~260 MB/s and Writes of 130~170 MB/s and latency of 0.1 they can easily out perform 3~5 HDD's in a RAID0 configuration. Yes 1 OCZ Vertex SSD is like having 3 or more Raptors in RAID0 ready to smoak you some data!
SSD's not only have the ability to hit the ceiling of the SATA bus with just 1 drive their access times are easily 100 times faster than desktop HDD. Even the fastest Serial Attached SCSI's can rank in at 3.x ms access which is at least 30 times slower than SSD.
I understand your enthousiasm about SSD disks but now you are just throwing numbers around like crazy without backing them up. Let me do that for you, however you might be disappointed by the result.
First off, access times. Yes, SSD is pretty much unbeatable with this, but no where near 100x. Even my several years old Raptor can do 8.x ms which is less, but newer disks will probably beat that. I will quote a site later, but it shows Raptors being at 7.2 ms. Raptors are readily available consumer desktop hard drives.
Then, performance, which you apparantly equal to read/write speeds. That is by no means a benchmark for performance. The site I refer to is www.tweakers.net which is a, or quite possible the leading dutch technology site. They have upward of 3 million hits a day, so they are pretty experienced with networking and (server) disk access. They wanted to do something with that knowledge so they made a professional benchmark database. They use several benchmark tools (IO meter, HD Tach) and even invented their own. Also they split up results so you can easily check several stats (write speed, access time, etc).
You say a Vertex SSD beats 3 or more Raptors in Raid0. Lets look at some benchmarks of write speeds.
Drive - #of drives - RAID Controller - Score (MB/s)
OCZ Vertex 30GB 1275 (run 1) 2 RAID 0 Intel ICH10R ***269,66 - is the highest Vertex score, 2 disk, Raid0
WD VelociRaptor WD3000HLFS 4 RAID 0 Intel ICH10R *****471,70 - is the highest Raptor score, 4 disks, Raid0
As you can see the Raptors still beat the Vertex by almost a factor of 2. And that's even with 2 Vertex disks, you claim one can even beat 3+ Raptors. Not gonna happen. So those are the real numbers. I still agree that SSD are awesomely fast, but nowhere near as fast as you say, and I got the numbers to back me up. Also, those disks cost shitloads of money. €185 for one 300gb Velociraptor, €115 for one 30gb Vertex. With the above raid setup, the Vertexes will only cost you €230. The Raptors will cost you €740, 3.2 times as much, but they will give you almost twice the performance and 20 times as much disk space as the Vertexes. Mentioned prices are cheapest online registered prices in my country, which is the Netherlands.
[edit] More numbers, this time disk-to-disk file copy (large file):
Drive - #of drives - RAID Controller - Score (IOps)
WD Raptor WD740ADFD 74GB 4 RAID 0 Areca ARC-1680 2GB ****6.667
OCZ Vertex 30GB (run 3) 2 RAID 0 Areca ARC-1280ML 2GB ***5.882