The i5 760 = 95W TDP and the GTX460 1GB = 160W TDP.
Add those up, and you're at 255W. You can add another 50W or so for the other components, if you don't have that many hard drives or fans. (eg. 2 HDD's + 4 fans), which still leaves you with enough room for capacitor again or even some slight overclocking, seeing as the CX400W is rated for 360W on the +12V rails in total.
Overclocking would increase your power usage in an exponential way: Power = Voltage^2 / Resistance
So I would actually stay away from it if you're going for a budget PSU!
The issue with the budget PSU's are that they don't come with 2x PCI-E connectors that you would require for a GTX460, AND that they're current that they can provide on the +12V rails usually aren't enough, although their total power that they can provide is.
Usually the peripherals (HDD's, CD-Rom & Fans) runs off the 2nd +12V rail, so do make sure that you have at least 4A spare on it!
A simple calculation would give you the minimum current that is required on the +12V rails for the CPU & GPU.
TDP / 12 = current. eg. 95W TDP / 12V = ~8A; 160W TDP / 12V = ~ 14A
So you'll need a PSU with at least 18A on its second +12V rail to be on the safe side of things.
Now the cool thing about the
Corsair CX400W is that it has a SINGLE +12V rail! Which means that it could handle a pretty high end graphics card / many peripherals as long as your CPU uses little power.
The
Gigabyte Odin 585 has 2x +12V rails (rated 16A & 18A respectively), which means that it is rated for about 408W on the +12V rail which is slightly more than the CX400W. Now the downside of the 2x 12V rails is that the one for the graphics card and peripherals is limited to only 18A, where you could've used about 22A for the graphics card and peripherals with the CX400W if you're using a i5 at stock speed.
The advantage with the Odin and its 2x 12V rails is that it can take a bigger CPU and allow you to overclock it without running into problems.
Unfortunately both of these 2 power supplies would require a Molex to 6-pin PCI-E adapter if you were to get a GTX460 that requires 2x 6-pin PCI-E connectors.
The Coolermaster GX550W doesn't have ANY of these problems, but then again, you pay twice the amount for it.