Need input to finish off my new build

Hello, I have gathered most of the necessary components, I need some advice/opinions to finish off my new build:

Approximate Purchase Date: Starting this week, I am going to be

procuring components over the next several weeks, I hope to have it up and

running mid-December

Budget Range: $600-$800 before rebates and taxes.

System Usage from Most to Least Important:

1. CAD work with AutoCAD, maybe Revit and/or some solid modeling, perhaps

some need for moderate rendering abilities.

2. General Microsoft Office apps - Excel, Word, Vizio, etc.

3. General internet surfing, streaming music, videos, movies etc.

4. Gaming (I was always strictly a console man, but I may want to get into

PC gaming)

Parts Not Required:

Mouse - I have two Logitech G700's and one G5

Displays - I am taking two Acer monitors with me from my workplace

(switching to working at home)

HDD - I will use an existing SAMSUNG HD103SJ, 1TB, 7200 RPM HDD

Discrete Graphics Card - I am thinking about relying on Intel's IG for the

time being, later I may add a discrete card, or cannabilize the GT-430 from

my other machine.

DVD burner/player - I plan to go without one for the time being; I am going

to attempt to install and boot Windows 7 from a USB flash drive.

Floppy Drive - No need.

OS - Existing Windows 7 license (non-OEM)


Components that I already purchased, but am counting towards the budget

total:

CPU - Intel i5-2500K quad core, non-HT; I purchased today at Micro

Center; Price: $179.99

Motherboard - ASUS P8 Z68-V Pro, purchased today along with CPU - it was a

bundled deal at Micro Center, $60 off. Price: before discount - $209; after

bundle discount - $149.99

RAM - Kingston HyperX KHX1333C9D3B1K2/8G, dual channel, DDR3, 1333, 8GB kit

(2@4GB ea); purchased today at Micro Center. Price: $34.99

Before Tax total price of components already purchased: $364.97


Components that I have yet to purchase:


Preferred Website(s) for Parts: NewEgg, but definitely willing to compare

with others; When they have the components that I want/need, I prefer buying

at Micro Center for the ease of being able to return/exchange parts in

person.

Country: U.S. - Denver, CO (I have access to a Micro Center).

Parts Preferences:

Case:
Option A: Fractal Design Define R3 Black Pearl Steel ATX Mid Tower Computer Case - Price on NewEgg: $109.99

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Option B: Antec Performance One Series P183 V3 Black Aluminum / Steel / Plastic ATX Mid Tower Computer Case - Price on NewEgg: $139.99

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Power Supply:
OCZ Fatal1ty 550W Modular Gaming Power Supply - Price on NewEgg: $69.99 (before rebate, which I am always too lazy too redeem)

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Before Tax total price of components yet to be purchased:
$179.98 with Case Option A
$209.98 with Case Option B


Before Tax Grand Total price of all components:
$544.95 with Case Option A
$574.95 with Case Option B


Overclocking: Yes, but with stock Intel cooler if possible

SLI or Crossfire: Maybe; the mobo I just purchased is set up for it

Additional Thoughts:

- I'd like some advice on the feasibility of overclocking the i5 with the stock cooler; how high should I dare go before creating an uncomfortable environment within the case? If I could get it somewhere above 4.0 GHZ on the stock fan, I think I would be a happy customer. The Fractal Design case I am looking at has the ability to install fans in the side and top, in addition to the included rear 120mm fan, if that makes a difference.

- Because my initial Grand Total is under budget, there is flexibility with my choice of cases. I picked those two out because they look a little more stately than some xtreme gaming chassis; I tend to like clean surfaces, no bulges or protrusions. I think I would like to stay away from full towers (greater that 20" high) since I don't think I would ever have 4 video cards at once or anything like that, maybe 2 at the most.

- I listed a psu for the sake of listing a psu, but I really don't know about this. I am thinking anywhere between 500W-750W would be fine, although, I don't really know what I will need in the near future if I want to add two video cards. I can't make up my mind between modular and non-modular. Price is not really too much of a concern; obviously if I can get a quality psu for $100 or less that would be ideal, but I could go between $100-$200, especially since it looks like I will come underneath budget for everything else. What about the psu's offered by Antec or Fractal Design? Are they any good compared to the one listed?