How much power will I need for my new build?

if you like Corsair get CMPSU-520HX 520Watt
http://www.amazon.com/Corsair-CMPSU-520HX-Professional-...

You will need a good 400-500watt unit with enough amps on the 12v rail. If on the cheap, you can grab a Antec EA 380D or a Corsair CX 430 V2 but seeing as you're looking at the HX series then I'll recommend the HX 650

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Powerful enough for anything you might do in the future and very high quality. I would also consider XFX and other Antec units in this price range as it's generally warranty and company loyalty since quality for most of the good units in this price range is nearly equal.

Depending on the case, you should add more case fans. The loudest part of your computer is the GTX 560ti so either way it doesn't hurt to increase your air flow.

Other than that, i might change the H61 to a z68 or p68 just incase you want to upgrade from the i3 to the ivy bridge or whatever Intel is releasing next year.

well, other psu suggestions are welcome as long as they are quiet and stable.
I only wanted HX because of how quiet everyone says they are, but I'm also having doubts about its high price on my modest build.

So, regardless of which brand it is, as long as it is as quiet and stable as those HX series, I'm fine.

I'm really trying to spend little money on this build (a nice well rounded computer for gaming, music, movies for the next 3 years)

I am running 3 systems, all overclocked, in Antec 900 cases (4 fans each - all set to LOW). The PSU's are one Corsair 750TX, one Corsair 550VX, and one Antec 550 watt TP3. The noisiest things I hear are the video cards.

Too much power is an oxymoron, particularly when you're thinking about adding/rebuilding your system in three years. I'm now in the process of rebuilding my system and I had to get a new power supply since the old one didn't have the power needed for the new video card. Unfortunately, I got cheep on the last build and didn't get a bigger unit. Now I've got a perfectly fine power supply that goes up on the shelf.

My Enermax Hoplite has three low-speed fans in it. When I turn it on, I can hear its four hard drives spinning up over anything else. The usual GPU is an Asus GTX560Ti, but it is also true of the PowerColor HD6670 I'm currently testing. The PSU is a Seasonic X560, which doesn't run its fan at low loads.
To allow a comfortable margin which will increase efficiency and longevity, I'd suggest a PSU in the 500W-550W range. Seasonic, Antec, Corsair, XFX, and Enermax/LEPA are among the better brands.

IMHO, you're asking the wrong question. You should use the biggest QUALITY PSU you can afford. Stressing a PSU is one of the worst things anybody can do to a computer or any electronic device. Think of the extra money as an insurance policy.

Thanks everyone for the advice.  

ram1009, well, while trying to figure this new build out, I really did find out the importance of a good psu. (I always went with no-brand psu's before, and the old computer is going nvlddmkm.sys on me, though i'm not sure if that is a psu-caused problem).

that's why i decided to pick up a branded psu this time around. but, the reason why i asked about the wattage was from reading tom's hardware SMB for $500 build. that had a 380W Antec in it. That got me thinking, even if I can afford a lets say HX520, won't I be wasting money? After all I won't be upgrading, rather I'll just buy a new system after 3 years.

But i see you point, and I'm thinking about going with a higher quality/power psu.

looking at all the reviews and prices for the suggestions given here atm.  
thanx guys!

p.s. without opening a new thread, i want to ask another question here. Regarding the chassis/case, should i opt for one with fans one the back, front or both? My old pc case don't have any fans on it   (Still looking for quietness)

Should be both. Fan's for intake in the front and fans in the rear for exhaust.

HX520 is a nice psu, it's also discontinued and hard to find.
Your system without a video card would draw around 100-110 watts from the wall running Prime, skip the math, figure about 85 watts DC.
The card pulls 162 watts ( DC ) gaming;
http://ht4u.net/reviews/2011/nvidia_geforce_gtx_560_ti_...
About a 250 watt load on the psu when gaming ( less than 70% of the 380's capacity )

Yeah, IMO, if you're just going to buy a new system it would be a waste to try and find an HX520.

lilo, thx, i'll do that.

dell, thx for the advice. very helpful. i guess i can save up a bit more money on this build then. i'll look for ones below 520W

seasonic 400W, they have a 'silent' one, i.e. the fan will only start at a certain temp & load, so browsing should be slient psu, and gaming will be louder psu but then you'll have game noise to cover it/ (i can't hear by S12-600.)

You're talking about the X series model which cost around $120. While the x650 is only $140 but in this range, you have many competing models to choose from.

OP. I'll recommend you some good quality ones for a good price.($50-80)
Antec HCG 520 $58.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Antec EA 650 $60
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Antec EA 500D $55
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
XFX 550W $ 70
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
SeaSonic S12II 520
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Corsair CX 500 V2
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Corsair CX 600 V2
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

thanks alot. didn't expect i'd get this many replies.   the forums quite active and helpful. great suggestions again. i'm looking through them right now.
i'm going out to assemble the computer in a few hours, so if there are any last minute suggestions or warnings you might have, i'd greatly appreciate it.

  can't wait for this build~
if it turns out well, i owe it to you ppl.