Decided on system, just need advice on CPU please!

Approximate Purchase Date: e.g.: In around a week or so.

Budget Range: 0-£580

System Usage from Most to Least Important: Gaming, Editing in Sony Vegas/After Effects, watching movies and web browsing.
Are you buying a monitor: No.

Parts to Upgrade: (e.g.: CPU, mobo, RAM) **Include Power Supply Make & Model If Re-using** All (Need advice on CPU)

Do you need to buy OS: Yes.

Preferred Website(s) for Parts: CCL or Amazon.
Location: City, State/Region, Country - Manchester, United Kingdom.

Parts Preferences: by brand or type: None.

Overclocking: Maybe.

SLI or Crossfire: Probably not.

Your Monitor Resolution: 1600x1200
Additional Comments: None.

And Most Importantly, Why Are You Upgrading: My current laptop sucks, I need a desktop.


Here is the build:

CPU: i3 2120 or Phenom II X4 965? Which one shall I get? I will be playing BF3 (Single & Multiplayer), GTA IV, Saints Row 3, Skyrim, Minecraft, etc.

GPU: Sapphire HD 7850 2GB
Link: http://www.amazon.co.uk/Sapphire-11200-00-20G-HD7850-GD...

MOBO: MSI H61M-P31 (G3) Socket 1155 Motherboard H61M-P31 (G3) or an AM3+ Motherboard depending on the CPU.
Link: http://www.cclonline.com/product/78779/H61M-P31-G3-/Mot...

RAM: G.Skill NT 8GB DDR3 1333MHz Memory Kit F3-10600CL9D-8GBNT
Link: http://www.cclonline.com/product/66091/F3-10600CL9D-8GB...

PSU: XFX Pro 550W Power Supply Unit P1-550S-UKB9
Link: http://www.cclonline.com/product/71543/P1-550S-UKB9/Pow...

CPU Cooler: Cooler Master Hyper TX3 EVO CPU Cooler RR-TX3E-22PK-R1
Link: http://www.cclonline.com/product/76741/RR-TX3E-22PK-R1/...

Case: Apollo Mid Tower Black Silver Blue Case CAS-881 (LED FAN)
Link: http://www.cclonline.com/product/72258/CAS-881/Cases/Ap...

HDD: Seagate Barracuda 500GB Hard Drive ST500DM002
Link: http://www.cclonline.com/product/66223/ST500DM002/Hard-...

So which CPU? i3 2120 or the Phenom? Please give reasons.
Thank-you.