A few comments:
For $3500 you could actually build 2 decent desktops (one for work one for school) and still have money left over for a cheap laptop.
@J2: Keep in mind that when you’ve got a 12 core machine like that, you’ll want more ram per core for rendering tasks. We have 64 gigs in our 16 core render farm because it balances out 2 gigs per thread. On a quad core laptop the benefit really isn’t there.
The OP is a student. Do you remember what kind of work you did as a student? Also a lot of stuff being mentioned is really specific to high end Viz. I don’t think the OP will be worrying about displacement issues running out of memory unless he’s at a point where he actually knows what that is and why he’d use it.
The biggest reason not to spec the machine with that much RAM is that it’s easy enough to upgrade and anytime you spec the machine with it from the start you’re paying for 3X the margins. Case in point - Upgrading the Thinkpad W he’s looking at from 16G to 32G is $360 - to buy it on Newegg is $120. That’s $240 that could have been spent on beer.
8-16G is plenty. I just decided to open Keyshot with a 800 meg rendering file, a couple full production product Pro E assemblies, a few hundred megs worth of Illustrator and Photoshop files, a 200 meg Alias file, + all my Firefox windows etc and I didn’t hit the physical memory cap and the machine was still running acceptably.
Don’t overkill what you can upgrade later for cheap.