Core i5 Gaming system for under $1500 CDN - Suggestions?

I am trying to assemble a new gaming system to augment my aging (7+ years) system. I (obviously) don't purchase new very often, so I am looking for something that is expandable and upgradeable. Crossfire/SLI is not necessary, but I want to keep my options open for the future. I've done enough research that I am sure I want to go Core i5 and with a Radeo HD 5850 based video card (even though they appear to be in short supply). I've read some of the posts and have spec'd out a system based on other people's suggestions. I am an IT professional, but this is the first time I've built a system for myself, so I appreciate any feedback. Oh, and if I can save money somewhere without sacrificing future expandability, that is, of course, a bonus.

I put together this system at DirectCanada.com:

Gigabyte P55-UD4P ATX LGA1156 P55 DDR3 2PCI-E 3PCI-E1 2PCI RAID 2GLAN CrossFireX SLI Motherboard $179.99
[url=http://www.directcanada.com/products/?sku=11830BD8966][/url]

Intel Core I5 750 Quad Core Processor Lynnfield LGA1156 2.66GHZ 8MB Cache Retail Box $218.88
[url=http://www.directcanada.com/products/?sku=12200BD3101][/url]

Arctic Cooling Freezer 7 Pro REV.2 CPU Heatsink Cooler LGA1366 LGA1156 LGA775 AM2 AM3 W/ 92MM Fan $21.94
[url=http://www.directcanada.com/products/?sku=10450AC0822][/url]

Arctic Silver 5 HIGH-DENSITY Polysynthetic Silver Thermal Compound 3.5 Gram $8.97
[url=http://www.directcanada.com/products/?sku=10460AC8077][/url]

G.SKILL F3-10666CL7D-4GBRH Ripjaws PC3-10666 4GB 2X2GB DDR3-1333 CL7-7-7-21 Core I5 1.65V Memory Kit $94.92
[url=http://www.directcanada.com/products/?sku=15380BD1255][/url]

Diamond Radeon HD 5850 725MHZ 1GB GDDR5 4.0GHZ 2XDVI HDMI Display Port DIRECTX11 PCI-E Video Card $282.83
[url=http://www.directcanada.com/products/?sku=11340BD3444][/url]

Antec Three Hundred Mini Tower Gaming Case 300 Atx 3X5.25 6X3.5INT No Ps Front Usb & Audio $61.82
[url=http://www.directcanada.com/products/?sku=10370AC8944][/url]

Antec Earthwatts 750W Power Supply ATX12V V2.2 EPS12V Active PFC 80PLUS 120MM Fan $114.45
[url=http://www.directcanada.com/products/?sku=10370AC7487][/url]

Western Digital SE16 500GB SATA2 7200RPM 16MB 8.9MS Ncq Hard Drive Oem 3YR Mfr Warranty $52.89
[url=http://www.directcanada.com/products/?sku=25350DR9550][/url]

Samsung SH-S223B/BEBE 22X DVD+-RW SATA DVD Writer Black OEM $31.90
[url=http://www.directcanada.com/products/?sku=14040DR6756][/url]

Microsoft Windows 7 Home Premium Edition 64BIT DVD OEM $116.60
[url=http://www.directcanada.com/products/?sku=12850SW2113][/url]

Kingston DataTraveler 410 8GB USB Flash Drive $27.37
[url=http://www.directcanada.com/products/?sku=12410DR9025][/url]

Logitech MX518 Gaming Grade Optical Mouse 1600DPI USB SILVER-BLACK $54.08
[url=http://www.directcanada.com/products/?sku=12660ID6649][/url]

Zalman ZM-RS6F 5.1 Channel Equivalent 6 Speaker Real Surround Headset W/ Microphone $48.75
[url=http://www.directcanada.com/products/?sku=15210AC1309][/url]

Altec Lansing VS4121BLK 3 Piece Speaker Stereo System $67.50
[url=http://www.directcanada.com/products/?sku=10350AC0370][/url]

Total $1,382.89

Thanks!

Hmm. I guess I need to add some details:

APPROXIMATE PURCHASE DATE: Next couple of weeks

BUDGET RANGE: $1,200 - $1,500 CDN

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: Gaming. Gaming. Oh, and Gaming. And web surfing, email, word processing, iTunes, etc. But we have computers that do that. So, mostly, gaming. Not really high end stuff, though. As long as I can play Lord of the Rings Online at highest quality without lagging in the 21st Hall, I'll be happy.

PARTS NOT REQUIRED: Keyboard is not required at this time. I have lot's of those. Unless someone knows of a really good quality backlit keyboard that's reasonable (i.e. under $50). I have a nice 24" LCD monitor that I will be using with this system.

PREFERRED WEBSITE(S) FOR PARTS: directcanada.com, newegg.ca. I open to other suggestions, as long as they are in Canada.

COUNTRY OF ORIGIN: Canada

PARTS PREFERENCES: Intel Core i5, Radeon HD 5850 based graphics adapter. Is one video manufacturer really better than another when the chipset is the same?

OVERCLOCKING: Maybe
SLI OR CROSSFIRE: Maybe

MONITOR RESOLUTION: 1920x1200

ADDITIONAL COMMENTS: Don't really need it to look really pretty. I'm more of a function over form person. Quiet is nice though. I really hate listening to a whole lot of fan noise or hard drive chatter.

Thanks again!

Wow, that's unfortunate, but your system is still great without them.