RAID-? (Need advice)

Okay guys, I have a single 250GB SATA150 WD and kind of want to start a RAID. I know these aren't the fastest drives (load times on UT2k4, Myst V Demo, and Stepmania are sort of slow), and I've got a little cash (not a LOT, so only stuff less than 10k RPM) to throw around, so I need some advice.

Terms: Great CPU/Gfx card/RAM, and I'm looking for a setup that'll be efficient for large games. Also, I have a bunch (~100GB) of movies/music/warez that I would really like to keep secure in case of a crash.

Options:
- Get 2x 250GB and do a RAID-5. ($230)
- Get 2x 250GB and do a RAID-4. ($230)
- Get 2x 160GB and do a RAID-0 for just games and boot (really fast?), and keep existing 250GB for storage. (Maybe RAID-1 later) ($170)
- More good options?

Thanks to anyone that can help.

>>3
Would the software RAID degrade performace a lot (If I were to do the RAID-0 option)? I'm on a AMD64 4400, so it's not like I really need _all_ of that power. Hehe. Oh, and yeah, I already have a drive for the higher RAIDs; I would need 2 more. (Why the prices are so high.)

>>4
P.S. I ALREADY HAVE ONE SATA 250 THANX FOR READING AND CONTRIBUTING HELPFUL INFO. ;D