Help me with my Hard Drive setup

Im doing a major upgrade to my storage sytem on my current system. My current system is made up of an Asus A7N8X Deluxe mobo, 40 GB IDE main drive with operating system, 80 GB SATA backup drive. Ive been using this system to do Video editing mainly and as you can see the hard drive space is just not big enough anymore.

This is how I want to setup the new hard drives:

Two 74 GB WD SATA 100000rpm main drive(s) set as RAID 0.
Two 250 GB WD IDE Hard Drives (not setup as raid) (used mainly for storage and backup of video, audio, software, photos, Image files)

As both sata slots will be taken up by the main drives could I use a Sata controller card to add another sata drive which will be used mainly for capturing video? Will the performance be lower with a conroller card than using the built in sata connections on mobo? Anyone know of a better way of setting up the drives? Should I get just one 74 GB drive and use the second sata connection for the capture drive?