Alright. Here is my situation:
I've been looking for a new laptop for quite some time (not really, it's been about 2-3 months ), and have finally found some laptops that look appealing. I have about 1,000 to spend, plus or minus 200 dollars. My laptop needs to be able to do moderate 3D modeling, light- medium graphics work, moderate gaming (mainly Source games, but i would like to be able to play more than that), and needs to be decently portable (so mid-sized screen). I'm not looking for a desktop replacemend, but rather a general purpouse laptop that'll hold me off 'till I get a desktop. I much prefer a metal case, as they're generally sturdier and don't gather fingerprints.
Hardware-wise, I've been looking for such:
-Sandy Bridge i5 (not a huge fan of i7 in laptops, have heard it greatly affects battery life)
-dedicated gfx card, w/ 1GB+ of dedicated RAM (I prefer Nvidia, but not a huge issue)
-500GB+, preferably 7200 RPM hdd
-4GB or greater RAM
-14"-15.6" screen, 1366x768 or greater
-not technically hardware persay, but I really do want a well-built laptop.

The two that I have seen that seem to match my requirements are the base-models of the Dell XPS 15z, and the HP Envy 14(the newer model). Reviews for them both seem to be favorable, but I have heard some complain about the build quality. Does anyone know anything about these laptops, or have similar reccomendations?

I, personally, got a Dell Insipron 15R for just such purpose. General use and all. I upgraded from the stock build ($600), so my finalized specs were:
- 15" screen
- Dual core i5 processors
- 4GB RAM
- 500 GB HDD
And I stuck with the stock graphics card since I already have a gaming laptop, but Dell.com's custom build stuff will let you choose an upgrade from Nvidea or ATI.
All-in-all the thing cost me just over $800, so if you upgrade the gfx card, too, it'll probably be somewhere in the $900 area.

But if you're set on one of your two choices, well..... since I haven't been looked into the laptop market for a while now, I haven't heard much about your them, but we have a Dell XPS Studio (the desktop version of that laptop), and it's a pretty high-quality machine.