mystikmind2000: Went to a website PCPartPicker (thanks to Dzsono) and put together a build based on what i have learnt so far.

How does it compare with the Ebay systems?

(Differences: Ebay systems have power supply, and a big standard HDD but do not have OS)

CPU: Intel Core i7-4770K 3.5GHz Quad-Core Processor ($395.00 @ CPL Online)
Motherboard: ASRock Z87 Extreme4 ATX LGA1150 Motherboard ($189.00 @ CPL Online)
Memory: Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory ($115.00 @ Mwave Australia)
Storage: Samsung 840 EVO 120GB 2.5" Solid State Disk ($108.00 @ CPL Online)
Video Card: Gigabyte GeForce GTX 770 4GB Video Card ($495.00 @ CPL Online)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) ($115.00 @ Mwave Australia)
Total: $1417.00

cjrgreen: I have an earlier version of that motherboard, and I really like it :)

You do need a case and a power supply, or all you will have is parts laid out on a table. And you really want a hard disk to keep from filling up that expensive SSD.

Power supply: You need a Haswell-compatible model. Bare minimum for that hardware would be a first-tier 500 watt model. Something like a Seasonic G 550W. Older Seasonics are not Haswell-compatible.

Case: I don't like flashy cases. Something like a Corsair 200R is inexpensive, no bulkier than it has to be, and easy to work with.

Disk: A 120GB disk will be full before you know it. Add a Seagate ST1000DM003 (1TB) or ST2000DM001 (2TB).

mystikmind2000: Apart from physical shape and wattage, what makes a power supply compatible or not?

cjrgreen: Haswell has a novel extremely low power sleep mode. Power supplies have a minimum current needed to maintain regulation, and many older-standard power supplies cannot work at sufficiently low current for this mode. Affected systems may fail to come out of sleep mode.

Power supplies that are Haswell compatible will state this in their specifications. Other power supplies are a poor risk with Haswell setups.

mystikmind2000: Well (warning, extreme sarcasm alert, possibly resulting in head exploding at the shock of how stupid things are in Australia), electricity is insanely expensive in Australia because of our huge population, massive manufacturing industries and so little space to build power plants and no natural resources to power them, such as coal or uranium...... So i would appreciate anything that saves electricity!

cjrgreen: We're pretty close. San Diego, California: US$0.275/kWh; last rates I saw for Australia, equivalent of US$0.29/kWh.

So we both gain from conservation.