Processor
.dual-core or quad-core
."OEM" label means an external heat-sink is needed
.Intel Processors

- Intel i7-3770k (1155 socket)
- Intel i5-3570K 3.4GHz/4MB (*)

Motherboard
.Socket type -> AMD's "AM2" socket, Intel's "LGA 1155" socket
.Size -> Mini ATX, Micro ATX, Full ATX
.# and types of external ports... PCI slots for extra USB adapters
.# of RAM slots
.don't need integrated graphics card (will buy separate)
.Number of SATA ports for hard-drives (at least 3 for my purposes?)
.Number of PCI slots -> extra USB, GPU, Sound card, LAN, Wi-fi Adapter
.Chipset (Important consideration for hacking purposes ***)
.ASUS, GIGABYTE, MSI

-ASRock Z77 Extreme LGA1155
-Gigabyte Z77X-UD3H (*)

Casing
.Size (Micro ATX mini tower is most common)
.Airflow (Have to read user reviews)
.Noise (Again, reviews)
.Number of drive bays (Optical drive, SD Card reader, etc. Need to pick carefully for internal hard drives as well)
.Ports (Front vs Back ports)
.Cable Management (To prevent airflow... see user reviews again)
.Antec, Cooler Master (Two best..), Termaltake, Rosewill, Lian Li are notable mentions

RAM
.Size (duh..4Gb vs 8Gb)
.Channels (Try to fill all channels.. e.g. two channels 4Gb, use 2x2Gb...)
.DDR3 (check motherboard supports this, very likely it does)
.top RAM speed (in case of over-clocking, 800/1066/1333 is most common speeds)
.Not much difference.. but Crucial, Corsair, Kingston, PNY, OCZ, G.Skill, Mushkin, Patriot.

-Corsair Vengeance 8GB (2x4GB) DDR3-1600 (*)

GPU
.NVIDIA has better support for Linux (hint hint)
.ATI/AMD cards are also good... but look at point one.
.XFX, EVGA, MSI, ZOTAC, ASUS, Sapphire
.http://www.anandtech.com/show/7703/desktop-video-card-buyers-guide-january-2014

-EVGA GTX780 Superclocked ACX 3GB (*)
-ASUS GTX780 DirectCu II OC 3GB
-MSI GTX780 Gaming OC 3GB
-Gigabyte Windforce GHz 1071MHz 3GB

Hard Drive
.Space (2x1 Tb?)
.Speed (7200RPM, 6.0Gb/s SATA hard drive if motherboard supports)
.SSD (Solid state drive... maybe not for now)
.Western Digital, Seagate, Hitachi, Samsung, Toshiba
.SSD -> Crucial, OCZ, Corsair, Intel

-WD 1TB Blue/64MB/EZEX/7200 x 2 (*)
-Samsung 840 EVO 120GB

Optical Drive
.Anything cheap lol

Power Supply
.Very important
.http://extreme.outervision.com/psucalculatorlite.jsp (Use this to calculate wattage needed for build, add 100 watts on top)
.Efficiency
.Cable Types (Modular, come detached from power supply. Long cables to ease headache)
.Noise (Read reviews)
.Corsair, Enermax, Enhance, Fortron/Sparkle/FSP Group, Hiper, PC Power & Cooling, Seasonic, SevenTeam, SilenX, XClio, Zippy
.Be VERY careful about this choice. Spend extra if have to for something reliable

-Corsair CX600M (600W) Modular (*)

CPU Cooler
.For cooling lol

-Cooler Master Hyper212X (*)