Thinking HDMI? Think RAID0.
This RAID review is very informative, especially the read/write tests.
If you've been considering RAID and RAID0 specifically then you must read this review.
Of particular note is that SATA II is default 1.5Gb/s and needs to be changed to 3.0Gb/s when configuring your RAID. (These speeds are the burst spec speeds.)