It usually takes me two months to build a rig, three if there's any special mods like painting or cable sleeving. I deal shop the whole time I'm building it, but most of the parts are pretty straightforward.
Asus Motherboard
G.Skill Memory
Corsair or OCZ SSD(s)
WD, Seagate, or Samsung HDD(s)
Seasonic PSU (no exceptions)
EVGA GPU(s) (or Sapphire if AMD is required for some reason)
Scythe fans and Noctua cooler (if not going liquid)
Cases are much more subjective (desired looks, possible mods, and space constraints) but I usually try to lean towards Corsair, CM, or Fractal Design
The only external sound cards I use are two Asus models and some of the HT Omega, but most people don't have an ear (or care to) for quality sound.
Dell screens, Saitek peripherals, not even going to start on speakers/headphones.
I don't just buy from newegg. If you live near a Microcenter, always buy your CPU from there (about $50 cheaper). Other than that, its usually alerts from bensbargains.net and the occasional tigerdirect purchase.
/nerd