You do not say what i7 you would get, there is a lot of difference between the i7 9XX and i7 8XX series processors.
Also 2.8GHz is a pretty low clock for an i7, most people who get i7's either overclock them or have the builder overclock them. The memory is not all that fast.
On top of that $3,800 sounds really high for what you have listed.
It would be helpful if you would list the major components with brand name and manufacturer part number, CPU, CPU cooler (HS) and fan, motherboard, PSU, hard drives, GPU, memory and case.
I purchased the PC in my specs from MaxForce PC and only paid $3,117 that included an overclock to 3.6GHz, I jumped it to 4.2GHz after I got it. The purchase price also included Office 2007 Pro and Win7 Ult 64b. This is almost $700 less than what Alienware (Dell) is quoting you. My price also inlcuded shipping.
If you are going to buy one because you do not want to build one, which I can relate to, I suggest that you email MaxForce a complete list of part numbers and ask Max for a quote. I can highly recommend Max.
http://www.maxforcepc.com/Rod
Asus R3E_i7 980X @ 4.44GHz_TR Silver Arrow_Mushkin Redline 6GB 1,644MHz @ 6-7-6-18_Zotac AMP GTX 480_OS - Windows 7 Ult 64b_OS SSD - Crucial C300 128GB_FSX HD - WD VR 600GB*2 w/3ware 9750-4i 6Gb/s Controller_Corsair AX850_CM HAF-X_FSX Gold, UTX, GEX, FSG,