Looking for energy efficient, budget desktop

Hi all, I'm in the market for a new PC, and mine can't run several recent games that I'd really like to play. Here's what I'm looking for:

• Budget is ~$600. Less, preferably of course.
• A bare-bones system is fine.
• I have an in-box ATI Radeon HD5670 video card, so a system with on-board video isn't a problem, since an immediate upgrade is on hand. (On the other hand, if I find a PC that has a roughly equivalent video card, the purchase is recent enough that I should be able to get a refund, so the price can go up some) It also requires a 400W power supply.
• I also have a sound card in my current system that can easily be transferred, and a decent monitor. Don't need those in the package.
• I would like something that's solid-to great now, and likely to handle new games for at least the next three years - this is making me lean towards a quad-core system.
• Energy efficiency is important, both for my bleeding heart and my electricity bill. This article: http://www.bit-tech.net/hardware/p [...] stigated/1 suggests that an AMD Athlon II Quad Core might be the best combination of efficiency and value. Also the Intel Core i3, but I've had a harder time finding it in quad core form.
• I can build my own PC, but I'd prefer to avoid that if the expense isn't significantly higher. Maybe it is.

Hello arkaeyn;

Try this on for size @ ~580
Using the CyberPowerPC Sandy Bridge Configurator tool
http://www.cyberpowerpc.com/system/CyberPower_H67_Configurator/

Using all standard options except:
Case: use Thermaltake V3 Black Mid-Tower Case
CPU: Intel Core i5-2300 2.8 GHz quad core
Cooling Fan: Intel LGA1156 Certified CPU Fan & Heatsink ** I'm certain they mean the stock Intel 1155 CPU cooler
Motherboard: GigaByte GA-H67M-D2-B3 Intel H67 Chipset
Operating System: Microsoft Windows 7 Home Premium (64-bit Edition)

If you're unhappy with a 5670 now, it's unlikely you'll be happy with it in a new system. What processor and PSU do you currently have? What game, resolution and detail do you want to use?

I think i would try for a better power supply with the cyberpower system. Name brand at least not extreme gear or cyberpower or raidmax.