okay... i buy everything on newegg.
but for each computer part, here is what i'll buy almost exlusivly (it'll take huge savings, or an act of god for me to go with any other brand)
cpu- ummmm duh... amd or intel, depending on price point
motherboard- asus, evga.... and maybe gigabyte
video card- EVGA, hands down. for amd/ati sapphire, xfx, visiontek
ram- crucial, kingston... maybe corsair
Hdd- Western digital, by far. then seagate
cases- lian li, silverstone, thermaltake, antec,
monitors- dell, samsung, viewsonic, NEC
for power supplies, there is a Tiered ranking system. i will link it, you want to build T3 or above. If you are not overclocking, a T3 power supply will be good for your machine. If you are overclocking, grab a T2 minimum. T1 are the best quality, and your 12V rails will be at 12V regardless how far you push your system.
pc power and cooling makes the best power supplies, period. if you are building a high end rig to OC, go pcp&c or go home.
seasonic and silverstone make high quality, quiet, highly efficient power supplies.
corsair is the best power supply value. they make very high quality psu's for a good price
coolermaster, thermaltake, enermax are all good
There is more to life than pew pew you know, like staying out of the fire so you can live to pew pew another day