I was having a discussion on raid performance at one of our LAN parties and promised to post pics from my setup, so here they are...

single Western Digital 250gb sata drive (cheap)
vs
dual Western Digital 250gb sata drives in Raid-0 (striped) (still cheap)

So, as you are about to see, the performance gain is almost 100% improvement. Of course, if one hard drive fails, the array crashes... so may sure to save disk images (Acronis True Image, Norton Ghost, etc) once a month to a secondary disk (recommend non raided in case of mobo failure).. for this i have another WD 640 gb hard drive.

So, ideally you set windows to be the first partition (20 GB in size), so you have fastest area of disk, and small partition to backup.
Then create other partitions for slower data (music, etc). The extra read and write speeds are particularly handy when transferring loads of data between hard drives and for video editing.

-Kevin

edit: my raid of 2 drives is less then ideal, i had an older revision of the 250 gb / 16mb cache from a few years ago and i raided that with a new 250 gb / 16mb cache blue edition that i purchased recently to raid with it...they have different speeds unfortunately....iden tical drives is best!

and here is a picture of a quad 250gb setup using the same drives, i picked it up from here: http://www.hardwarecanucks.c om/for...f-932-a-2.html

Now compare this 1TB storage, 235 MB linear read, for roughly 200$ (50$/drive)... to a 80 GB Solid state drive with similar read specs for 200$!
Of course, SSD performs better for random read, but suffers on random/small writes!

Also, i would recomend Western Digitals 640Gb blue/black edition drives. They are at an excellent price point (75$ ish), and have 100/110 MB/s average transfer (blue/black edition). Imagine them in raid, once i get a new mobo with more sata connectors maybe i will do that for fun. I can post the HdTach benchmark of the 640 blue if anyone wants to see it.

either of these drive practically beats the 10k RPM 150GB WD VelociRaptor drives that cost three times as much...
http://techreport.com/articles.x/14380/13 HDTach scores compared to other drives
http://techreport.com/articles.x/14380/15 Summary