For desktops, I prefer custom built. Some brands I'm quite loyal to are XFX for video cards, Corsair for RAM, Intel for processors, and Western Digital for hard drives.
Western Digital has great Hard Drives. Got a 3TB for $120 with my employee discount at Target a few months ago and I've had absolutely no problems with it. And Sandisk makes great USB and SD cards with low prices in mind as well. Got a 16GB Cruzr Blade for $10 on Black Friday.