Need a new desktop (a few related questions) - Sub $600

Looking to purchase a new desktop in the next few weeks.

I just got a new Chase Freedom credit card with the $300 cash back solely for this purpose. That being said, my budget is $500-600.

Would prefer an i5 or i7 machine that comes with a Windows 7 OS.

4GB memory/500gb storage are probably what I'd want as minimums but not too strict about those. I have somewhere in the neighborhood of 16gb of unopened DDR3 memory already (so something that can accept 16gb would be nice), and a few TB of external storage (which is where I keep most of my media so 500gb of on-board storage would be more than enough, I'd probably really only need 120 or less).

I'm not really a gamer so don't need a gaming rig, but have kinda been interested in getting into light-weight gaming (nothing serious at all).
I used to do some 3D modeling which my current computer (a 5 year old Dell Laptop) can just barely handle, though the actual 3D rendering process (add photo-realism to the 3D model) can bring my current system to its knees which pretty much made me give up my hobby. Something that can handle that would be great.

Plenty of USB ports would be nice for charging all of my gadgets; USB 2.0 a minimum obviously, but at least one USB 3.0 would be sweet.

HDMI would be nice but not necessary.
A TV tuner would be nice but definitely not necessary.

I don't need any peripherals. Have plenty of keyboards, mice, monitors, etc.

I know $600 as a price ceiling may seem pretty low for this kind of build, but keep in mind that I'm perfectly fine with purchasing an open-box or outlet system as long as it comes with a decent (preferably same-as-new) manufacturer's warranty (I'd even consider refurbished). Also, again, I don't need any peripherals at all.

Any suggestions? I know of a few places to look (mostly the outlet sections of major brand websites) but any other places I should check?

With the usage-based needs that I've described above are there any particular components I should be looking for (e.g. a specific graphics card)?

The second part of my question is about the timing of my purchase:
Should I try to take advantage of the last few days of pre-Christmas sales push deals or would it be better to wait until after Christmas to find the best deals? I figure if I wait til after Christmas I may be able to take advantage of returns, open-box and cancelled-order units.

Building it yourself isn't an option?

Quote from prozac4312 : Building it yourself isn't an option?

I plan to build one myself but not this one.

I'd like to have someone else to blame should I have any problems (i.e., I want a warranty).

Quote from richiejn : I plan to build one myself but not this one. I'd like to have someone else to blame should I have any problems (i.e., I want a warranty).

449.99 Gateway DX i5 2300 8GB 1TB [newegg.com]

http://outlet.lenovo.com/desktops...27xb4.html
http://outlet.lenovo.com/desktops/ideacentre/77273hu.html

Yup, wait about a week after christmas & then start looking in http://outlet.lenovo.com and http://outlet.dell.com

Dell Outlet [dell.com]is now offering 15% off on all desktops & laptops.

Here's my self- promotional link to the xps 8300