I do cad too, Autocad to be exact. That's a pretty high spec system for it. If you're not running a lot of rendering and realtime 3D visualization, you might want to save a bit of money and run the specs down a ways. Best bang for the buck is definitely going to be ram and HD Raid 5. Under normal operating circumstances, doing 2D drawing in Autocad, you're pretty much never going to see the CPU jump above 10%.
I'm big into gaming too though, so a higher spec system is a good thing in my opinion. I'm working on getting the $ together for my next build. I'm going with a triple monitor setup, Core 2 Duo 6600, 4GB ram, (3) 500GB Seagate Barracuda HD's in a Raid 5. I've priced up to about $2K, not including the case, lighting or optical drive(s). Also not including monitors, KB, mouse. My preference for running CAD on it will be to get the highest resolution monitor possible for the center screen. (You can push toolbars from Autocad onto other screens, but when you restart they end up back in the upper left corner.)
Blu-Ray is far from being a leading industry standard. It's the VHS/Beta war all over again. I'm sitting it out. I'm not replacing my TV, surround reciever, etc just for a bump in video quality. And as for optical storage, unless you're making high end video, it's total overkill. A DVD toaster will run you south of $30 if you look in the right places. A Blu-Ray drive is still somewhere in the stratosphere. Hard drive storage is super cheap by comparison. That's where I'd stick my bucks.
The other top of the line components make me drool a bit, but it really is a little over the top. I've not seen anybody out there that needs that much machine... unless they're completely stuck on impressing the folding@home people... that can be addicting. Just make sure that hardware isn't going to waste!