taking out all the extra spaces makes viewing your post much easier. please keep that in mind. as far as your criteria "gaming rig", "most amazing system" and "will last a long time" i'm confused by the parts you picked out.
what exactly is it you want? do you want a machine that is capable of web browsing, office tasks with a very minimum of gaming? if so you can get away with cheaper hardware but you will not be able to play demanding games. what determines your hardware requirements are the most demanding tasks you will be using it for. for instance if you want to play "the best and greatest" games but only part of the time then you will still be needing a beefy system even if 99% of the time you are text editing.
we need a better description of what you need but i will do a few preliminary comments. my comments will be listed under the price with a dash "-".
LITE-ON DVD Burner - Bulk Black SATA Model iHAS124-04 - OEM Item #: N82E16827106289Return Policy: Standard Return Policy
-if you wanted to you could save a few bucks. i've seen drives go $10 or under but thats up to you. in any case it should work. suggest lightscribe.
Rosewill BLACKHAWK Gaming ATX Mid Tower Computer Case, come with Five Fans, window side panel, top HDD dock Item #: N82E16811147107Return Policy: Standard Return Policy
-$10.00 Instant $99.99$89.99
-suggest case with 120mm fan holes. also suggest hdd rack if possible. cable management locations are helpful as well. take a look at the antec 800 or HAF.
Western Digital Caviar Blue WD5000AAKX 500GB 7200 RPM SATA 6.0Gb/s 3.5" Internal Hard Drive -Bare Drive Item #: N82E16822136769Return Policy: Standard Return Policy
-$10.00 Instant 99.99$89.99
-if anything buy the caviar black over the blue. oem drives are fine. no need for 6gb/s as a normal hdd cannot reach this range. sata II is fine. you can get a 1TB black sata II drive for $100!!
EVGA 01G-P3-1460-KR GeForce GTX 560 (Fermi) 1GB 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card Item #: N82E16814130660Return Policy: VGA Standard Return Policy
$15.00 Mail-in Rebate Card $189.99
-looks like a reasonable choice to me. cannot go wrong with evga.
CORSAIR Enthusiast Series TX750 V2 750W ATX12V v2.31/ EPS12V v2.92 80 PLUS BRONZE Certified Active PFC High Performance Power ... Item #: N82E16817139021Return Policy: Standard Return Policy
$15.00 Mail-in Rebate Card
-750w should be sufficient. corsair seems to make a decent psu as well. make sure you double check included cables with the power cables you need for your mb, vidc and other connections.
ARCTIC COOLING Arctic Cooling MX-4 AC-MX4 4 gram (g) All-Around Thermal Compound Item #: N82E16835186038Return Policy: Standard Return Policy
-personally i always use "artic silver" but you are correct in that applying your own thermal paste on the cpu is a good idea.
G.SKILL Ripjaws X Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL9D-8GBXL Item #: N82E16820231428Return Policy: Memory Standard Return Policy
-personally i prefer ocz or mushkin. for a dual channel system 2x4 is fine. another option might be to go 4x2gb sticks as the larger sticks tend to be a little slower. up to you.
ASRock Z68 Extreme3 Gen3 LGA 1155 Intel Z68 HDMI SATA 6Gb/s USB 3.0 ATX Intel Motherboard Item #: N82E16813157271Return Policy: Standard Return Policy
-$8.00 Instant $129.99$121.99
-up to you just make sure you have all the features you want and that all of your parts are compatible. personally i prefer dfi or asus boards.
Intel Core i5-2500K Sandy Bridge 3.3GHz (3.7GHz Turbo Boost) LGA 1155 95W Quad-Core Desktop Processor Intel HD Graphics 3000 ... Item #: N82E16819115072Return Policy: Iron Egg Replacement-Only Return Policy
-would suggest an i7 even if it is one of the older models. you can get a new model in your budget if you fidget it a little bit around.
Microsoft Windows 7 Home Premium SP1 64-bit - OEM Item #: N82E16832116986Return Policy: Software Standard Return Policy
Crucial M4 CT064M4SSD2 2.5" 64GB SATA III MLC Internal Solid State Drive (SSD) Item #: N82E16820148441Return Policy: Limited Replacement Only Return Policy
-$35.00 Instant $139.99$104.99
-keep in mind that you will easily fill half of that with just the OS, drivers, basic programs and maybe one game. it definitely makes windows snappy though. personally i use an ocz vertex II.
CORSAIR CWCH60 Hydro Series H60 High Performance Liquid CPU Cooler Item #: N82E16835181015Return Policy: Standard Return Policy
-$5.00 Instant $74.99$69.99
-one question... why? the stock coolers are perfectly fine for even an i7. in fact i would use this money you saved on the liquid cooler to put into an i7 over an i5. i know my i7 fan has never went over 30-40% even when i tried out crysis for a few hours. if anything the video card is what will be making the noise usually. good case airflow (larger cases) help out here alot as well since overall temperatures are normally much less than a small case.