Need Advice on New Budget PC

Hello everyone I'm building a new pc mainly for gaming and I need your opinions in this:


Budget Range: about $450  

System Usage from Most to Least Important: Gaming, surfing the internet, editing photos and movies

Parts Not Required: keyboard, mouse, monitor, speakers, OS, HDD

Parts Preferences: Intel CPU, Nvidia

Overclocking: No

SLI or Crossfire: No

I already choosed :

CPU: Intel Core i3 2120

Chasis: Thermaltake Commander MS-I

and I will be adding an additional Fan: SickleFlow 120 2000 RPM Blue LED

Power Supply:
Thermaltake Litepower 450W 80 PLUS Bronze

RAM: Kingston 4GB DDR3 1333MHz ValueRAM (I plan to increase it later)

VGA:
GeForce GTX 550 Ti OC Windforce 2X

or

Galaxy GeForce GTS 450 1024MB GDDR5

Motherboard: ASUS P8H61-M LX

or Gigabyte GA-H61M-S2P


I was wondering if a 450 w power supply would be enough for these components

and which mobo and VGA should I go with

I plan to play games like: Battlefield 3, Skyrim, Black Ops, Mass Effect 3, Assassins' Creed, Crysis


thanks in advance   I really appreciate your help