lealla, that is about the right on the money for a $1500 build. however, 150 for psu and case can result in skimping. in my experience, the power supply is the single most important part of a computer. it directly affects how well your pc performs, and how much you spend operating it. im not saying you need a $300 1200W psu, that is only necessary for the mightiest of systems.
modular power supplies (costlier) allow you to only put the cables in yoru computer that you need.
this is nice in a gaming rig, because mostly all you have is essentials, (not 5 hdd's and 3 optical drives), so you don't need all those molex cables to begin with.
i would reccomend at least an 80+ certified power supply. if your computer parts uses 400w (DC) of power (that a more high power system than most people think), and 85% psu uses 471 (AC) watts from the wall. a 70% (most cheap power supplies) will use 571 W (AC) from the wall. if you pay your electric bill, you will immediatly see those savings. that 100w of power you save will light your house (if you use the green 15w lightbulbs). i like using less power, and so does my wallet.
a nice case makes your build experience. a crappy case can/will cut you up. it will also provide headaches on what to do with the wires. nicer cases have cable hooks to help rout your cables to provide clean airflow.
those are my 2 cents.
i wouldn't even think of buying an icore7 build for under 2000 right now. its not worth it at the 1500 price point, at least imo. i enjoy quality parts, and i would rather go for a phenom II at 2.8 ghz for 190 and an amd mobo for 130, and buy a 150 dollar case and 150 dollar power supply and grab 4 gigs of ddr2 and push it to 1200. but its a $300 dollar premium to go for an icore, and at $1500, thats a 20% premium, for a less than 5% increase, most of which you cannot see with a single graphics card set up.
There is more to life than pew pew you know, like staying out of the fire so you can live to pew pew another day