Fuck yeah! Just got my Linux software RAID 5 array working.
Setup:
3x Seagate 7200.12 1TB - $269
Asus M2R32-MVP mobo - $free
Athlon X2 4050e - $35
Crucial 1GB DDR2 - $10
Intel PRO/1000 Dual 1Gbit NIC - $free
Antec TruBlu 480W PSU (although I heard bad things about it) - $20
2U rackmount case - $free
I was going to put Ubuntu on it, but it didn't like my PCI video card I was using to get this machine setup. Ended up just downloading CentOS and installing it. The software RAID 5 works AMAZINGLY well. I was able to rip out one of the SATA drives while the whole thing is running and viola, it continues running on two drives and then once I plug it in, the system rebuilds the array if need be. All on the fly!!
$350 got me a 2TB RAID 5 setup with the ability to add more drives.. not bad at all.
The RAID setup is as follows:
100MB /boot on drives 1, 2, 3 as RAID 1 with one spare
1GB swap on drives 1, 2, 3 as RAID 1 with one spare
1.9TB / on drives 1, 2, 3 as RAID 5