Going to be using my system for HD video capture, and from what I understand, I will need a write speed of about 130mb/s. Will a raid 0 setup be able to handle those speeds? Was thinking of two 500gb sataII 7200 drives.
If you're working with uncompressed video, you need to ask your editing station/editing software manufacturer what they recommend. Frequently, with high end editing systems, the manufacturer has tested their software only in particular system configurations. They won't support you if you deviate from their recommended setups.
Four drives in a RAID 0 can be fast enough for uncompressed capture and uncompressed editing if it's done correctly (i.e. proper motherboard and chipset, proper RAID card and interface, etc.)
RAID 5 can be quick for sequential access with the right RAID card (the 3Ware 9650SE can do 600MB/sec writes in RAID 5 with 12 drives). RAID 5 random writes are always slower due to the limitations of write combining. RAID cards with large amounts of cache can help the overall speed by allowing more write combining.
To really make a quantified statement as to how much speed you're going to need, we need to know the editing platform, codec it uses, and tape formats you'll be working with. If it actually works with 4:2:2 uncompressed video, you definitely need to get the technical requirements from the editing software manufacturer instead of trying to build something yourself.