New build on a short Budget

[DreamSpyre]

I'm looking for a good amount of performance in as little money as possible really. I want to be able to play WoW on max Settings, and have the option of playing SWToR at high settings, if not maxed. My budget is roughly 600, but the lower the better really. This is what I've come up with so far;

Case - 39.99
NZXT GAMMA Classic Series GAMA-001BK Black Steel ATX Mid Tower Computer Case

GPU - 109.99
ASUS ENGTX550 TI DC/DI/1GD5 GeForce GTX 550 Ti (Fermi) 1GB 192-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card

PSU - 39.99
ENERMAX NAXN ENP450AST 450W ATX12V Power Supply

Memory - 51.99
CORSAIR XMS3 8GB (4 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory Model CMX8GX3M4B1333C9

Mobo - 79.99
ASRock H67M (B3) LGA 1155 Intel H67 HDMI SATA 6Gb/s USB 3.0 Micro ATX Intel Motherboard

CPU - 124.99
Intel Core i3-2100 Sandy Bridge 3.1GHz LGA 1155 65W Dual-Core Desktop Processor Intel HD Graphics 2000 BX80623I32100

SSD - 90.99
OCZ Solid 3 SLD3-25SAT3-60G 2.5" 60GB SATA III MLC

Total: 537.93

I already have Monitor, Mouse, Keyboard, Speakers and a 500gb WD Hard Drive to throw in with this. Any rough idea how this will run? I am sorta concerned that the PSU isn't powerful enough. Would it at all be possible to throw in a more powerful PSU that will work for this setup while staying around the same pricepoint, or even adding another hard drive in while keeping it under 600?

[chaud]

Get a P67 board so you can at least drop in a better CPU and overclock in the future. That PSU looks like junk, this one is a better choice.

Spend another $20 and get a useful GPU.