Ok, SATA 150 and SATA2 are the same thing, but SATA2 has faster transfer speeds. SATA2 HDD's are backwards compatible with SATA150, but they will run at SATA150 speeds. A SATA150 HDD cannot be used on a SATA2 board.
RAID 0 is when two or more HDD's are recognized as one big HDD in Windows XP. They interlace the data between the two HDD's. Here's how it works:
HDD 1 holds file A
HDD 2 holds file B
HDD 1 holds file C
HDD 2 holds file D
Like that. This way is the faster of the two. The catch is: if one HDD fails, all data is lost.
RAID 1 is where you have two or more HDD's shown as one in Windows XP. The difference is, only one HDD is used, and the other is an exact copy of the first. This is the safer way, but is only as fast as one HDD is.
In a nutshell; RAID 0 is faster, but not as safe (in terms of data loss) and RAID 1 is slower, but safer.
If your budget allows you to, I would get two of those HDD's. Though, if you can only afford one, you can always pick up another one later on. You won't be dissappointed with the speed of a SATA2 HDD anyway.
By the way, make sure the motherboard you buy is compatible with SATA2.
I hope this long *** post made some sense.
