(prices from NewEgg Canada unless otherwise noted)
CPU
Intel Core i5-2500K Sandy Bridge 3.3GHz (3.7GHz Turbo Boost) 4 x 256KB L2 Cache 6MB L3 Cache LGA 1155 95W Quad-Core Desktop Processor BX80623I52500K
$229 http://www.newegg.ca/Product/Product.aspx?Item=N82E16819115072
Motherboard
BIOSTAR TP67B+ LGA 1155 Intel P67 SATA 6Gb/s USB 3.0 ATX Intel Motherboard
$130 http://www.newegg.ca/Product/Product.aspx?Item=N82E16813138298
(This was the only LGA1155 + P67 board on NewEgg.ca. I wouldn’t buy that motherboard yet, since they are just now coming back out I think you’ll get a better deal if you wait for others to be available. Plus they're trying to rip you off for $11 shipping on this. So shop around in a couple of weeks for a diff't motherboard. You want socket type LGA1155 and Chipset P67, pretty much everything else is optional)
Three choices for
Video Cards:
$180 ($200 - $20 Rebate) XFX HD-685X-ZDFC Radeon HD 6850 1GB 256-bit DDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card with Eyefinity
$175 ($205 - $30 rebate) ASUS EAH5850 DIRECTCU/2DIS/1GD5 Radeon HD 5850 (Cypress Pro) 1GB 256-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card w/ Eyefinity
http://www.newegg.ca/Product/Product.aspx?Item=N82E16814121375
$230 SPARKLE SX560T1024D5MH GeForce GTX 560 Ti (Fermi) 1GB 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card
I would recommend the 5850. As confusing at it may seem based on the naming/numbering, this 5850 performs better than the 6850… and it’s cheaper to boot. Rebate makes this the best bang for buck atm IMO. The 560 Ti is listed because it's also a good value, just at the next higher performance level. So if you're willing to spend a little more then the 560Ti gets my vote.
Memory
$55 G.SKILL Ripjaws Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory Model F3-10666CL7D-4GBRH
http://www.newegg.ca/Product/Product.aspx?Item=N82E16820231276&cm_re=G.SKILL_Ripjaws_Series_4GB_%282_x_2GB%29_240-Pin_DDR3-_-20-231-276-_-Product
Hard Drive
$50 SAMSUNG Spinpoint F3 HD502HJ 500GB 7200 RPM 16MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
http://www.newegg.ca/Product/Product.aspx?Item=N82E16822152181
Power Supply
OCZ ModXStream Pro OCZ600MXSP 600W ATX12V V2.2 / EPS12V SLI Certified CrossFire Ready 80 PLUS Certified Modular Active PFC Power Supply compatible with core i7
$75 ($90 - $15 rebate)
http://www.newegg.ca/Product/Product.aspx?Item=N82E16817341017
Operating system
Microsoft Windows 7 Home Premium 64-bit 1-Pack for System Builders - OEM
$110
http://www.newegg.ca/Product/Product.aspx?Item=N82E16832116754
If my math is right we're at about $824 (not counting shipping).
Pick a case that you like, there are plenty within the $50-75 range. I wouldn't go much lower than that. Look for something w/ at least two fans, and if you can find something with speed controls for the fans that's even better because it helps you manage the noise created.