What sort of power supply do I need?

Your power needs are minimal. The antec earthwatts 430 you ask about is a good fit for many reasons:

1) properly sized

2) Not overly expensive

3) relatively high quality

4) efficient

Under full load, your system is going to use about 200W (total). The problem with sizing a power supply for a system like yours is, there are no decent quality power supplies below 380W anymore. So you'll have to go with 380W or more (or else you'll be buying garbage quality).

The Antec 430 you ask about will run between 30-40% load factor, constantly. Not only will this be good, as far as energy efficiency goes...but it should be very reliable in the long run.

With a Radeon HD 5750 your build requires a minimum 450W PSU (although that Antec 430W could probably squeak by). I recommend the Corsair CX500 as a good budget choice.

Top PSU brands include Seasonic, Antec, Corsair, XFX, Silverstone, Enermax and OCZ.

Low-quality brands include Apevia, Diablotek, Logisys and Coolmax.

When shopping for a PSU, you should look out for these few essential things: 80+ certification, high-amperage +12v rail, the number of rails, cable lengths and types, modularity, brand and etcetera. It is best if you'd pick a quality PSU - the more efficient the PSU, the lower your electric bill. Not only you save your electric bill, you might also prevent your motherboard from being fried in the future and/or elongate the longevity of its life.

If you're not planning to SLI/Crossfire in the future, then I'd recommend getting a 500w - 600w SeaSonic's or Corsair's PSU, those two brand are currently known as the top-tier brand.

With that configuration,the best PSU for you will be a CORSAIR CX 500 Watt PSU.It is the best PSU in budget category range and provides continuous and full 500 Watts of power.

Your power supply depends on what you are going to use your computer for. If it's going to be a family computer or something of the sort you should be fine with something around 350w - 425w(ish). The one you currently have is way too powerful. If you were to use that one you would almost definitely fry all of your hardware, especially since your CPU isn't meant for overclocking.

If you just want it to be a simple gaming rig, I would recommend probably 450w - 500w. I would also recommend a power supply from a well-known brand such as corsair or antec or cooler master.

Either of these should be fine:

http://www.newegg.com/Product/Product.aspx?Item=N8...

http://www.newegg.com/Product/Product.aspx?Item=N8...

pcpartpicker.com is also a good website because they compare prices from multiple sites.

With that configuration, the best PSI for you will be a CORSAIR CX 500 Watt PSU.It is the best PSU in budget category range and provides continuous and full 500 Watts of power.

If you're not planning to SLIT/Crossfire in the future, then I'd recommend getting a 500w - 600w Slavonic’s or Corsair's PSI, those two brand are currently known as the top-tier brand.

If you just want it to be a simple gaming rig, I would recommend probably 450w - 500w. I would also recommend a power supply from a well-known brand such as corsair or antic or cooler master.

If you go with a cheap PSU . get a 750+ watts

If you go with a good (known) brand, you can go 500-650 watts, but make sure its rated %80 efficiency!

Best are, antec, apevia, corsaie...