I'm looking to build a new computer for about $1200. Mostly it will be used for playing WoW, LOL and SCII. I live in Canada and I'm about 5 minutes away from a memory express so I'm planning on just ordering the parts from memory express since I can just go pick them up at the store. I'll be reusing my current monitory/keyboard/mouse. I have a decent amount of experience mucking around with computers, but I've never built one from scratch myself so I'd appreciate any feedback on my planned build. I'm particularly clueless about what to look for in a case/power supply as I've never had to shop for those myself before.
CPU: Intel Core™ i5-3570K Processor, 3.40GHz w/ 6MB Cache $229
Motherboard: P8Z77-V LK w/ DDR3, 7.1 Audio, Gigabit Lan, CrossFireX / SLI $144.99
Memory: G.SKILL RipjawsX Series 8GB PC3-10666 Dual Channel DDR3 Kit (2 x 4GB) $52.99
SSD: OCZ Vertex 4 Series SATA III Solid State Drive, 128GB $119
HD: WD 1TB Caviar Black 7200rpm SATA III w/ 64MB Cache $99
DVD: Asus DRW-24B1ST 24x DVD-RW Drive, SATA, Black, OEM $19
Video Card: Gigabyte GeForce GTX 660 TI 2GB PCI-E w/ Dual DVI, HDMI, DisplayPort $299
Case: Cooler Master Elite 330U Case $54
PSU: Silverstone Strider Essential 500W Power Supply $60
OS: Windows 7 Home Premium x64 (64-bit) SP1 $120
With tax this all comes to $1263.