Should I build a custom?

[Frobot]

I have been planning on getting a new computer very soon, and until recently I was sure I wanted to just buy one from a store.
The Alienware Aurora was what I had decided on, but after some research I always hear that you can custom build the same thing for much less.

The problem is I have no experience in building a computer. I can't afford to mess something up either. I do know a little at least. I have changed out gfx cards, ram, hard drives, etc.
How hard would it be to pick up on, and how might I go about doing it?

I already have a nice case and two hard drives I could use.
I want to at least match the computer I was going to get though.
8gb+ quad channel ram, processor at around 3.4+, and a high end gpu.
How much money might I save, and will it be worth the effort?

 

[OhSnapWord]

How much are you willing to spend on the machine?

 

[Frobot]

between 1-2k was what I was planning on, probably closer to $2k

 

[OhSnapWord]

What was the computer you wanted to get?

Most motherboards with the X79 chipset support quad channel RAM and are LGA 2011. This would be a good starting point as the motherboard largely determines the rest of the system.

 

[Frobot]

I wanted an Alienware Aurora which comes out to 1,600 on their website.
4 core i7 @ 4.1 ghz
8 gb quad channel ddr3
gtx 555