RAID 0+1 is overkill. It forms a striped (RAID 0) array out of two mirrored (RAID 1) arrays. Not necessary.
Since she's doing 3D modeling, a larger screen is nice. While I'm doing programming, the larger the screen the better. The Viewsonic VX2025WM is what I'm using now, and it's basically an orgasm that plugs into the wall. 20" of LCD is great, and the refresh rate is awesome, no problems staring at it for hours at a time.
Since her work is on the machine, I'd suggest not overclocking. Believe me, an e6300 or e6400 will provide plenty of power. Keep in mind that most of the people on here are gamers who have mulitple machines, if you ask the few that do more work than play they're mostly running stock clocks. It's not worth the risk if your work resides on it.
For video card, I'd say to get a workstation card, but $1500 doesn't leave much leeway. Get an eVGA card with at least 512MB of video ram, the extra texture memory really helps with a higher-resolution screen and larger models. SLI or Crossfire...meh. I don't think it's useful enough to warrant another video card, especially since $1500 doesn't really allow it.
For cooling, don't get anything too heavy or tall. I'd say you shouldn't need anything quieter than the stock cooler. See how it goes, try it out for a while, and if it's too loud then you can change it. If you get a quiet case, without a window, something like one of those Antec Sonata II cases, fan noise should be irrelevant.
For those who are saying not to use DDR2-800, you'll be choking the performance of the Core 2. Memory performance is critical when doing anything 3D-related. Besides, it's not that much more expensive, even for Corsair's XMS series. Fortunately, Intel CPUs aren't as sensitive to CAS latency and timings as AMD CPUs generally are, so you won't notice too much of a difference with slightly slower timings and CAS latency.
Core 2 Duo e6300
GIGABYTE GA-965G-DS3
2 x WD Caviar RE 250GB drives
2 x 1GB Mushkin DDR2-800, 5-5-5-12
eVGA GeForce 7950GT, 512MB
Viewsonic VX2025WM 20" LCD display
Antec Sonata II case, with 450W PSU
Windows XP Pro
Samsung DVD burner w/ Lightscribe
Total = $1279
The rest is up to you. The only thing you could possibly need to upgrade would be the PSU, but Antec knows their power supplies. That 450W will power that build with no problems. If you wanted to upgrade the video card to a DX10 model eventually, you'd want a new PSU. But that's in the future.
Good luck!