Need help with hard drives (RAID?)

I'm building a high-end system off the i7 core, and will probably use a 500gb hard drive (raptor? 7,200?), then later add another 500gb. I was wondering, 1st, is it worth going with RAID 0, or is the speed benefit pretty minor? also, what's a good hd speed? I have heard that higher speeds are more prone to wear out sooner, but they are faster. Is that enough of a concern that I should stick to a 7,200 rpm setup, or can i go faster without any real concern about shorter lifespan. I will probably be using my system for web editing/photoshoping, along with probably some gaming. I'm kinda new to this, so thnx in advance for the help