CPU - whatever you want, all fanboys will tell you differently.
Ram - Kingston/Crucial/Corsair/Micron/(samsung) a little further down the list
GFx - Again all fanboys will tell you differently ATI is what I use but I've been going to lean towards Nvidia
Mobo - Abit [went back to them]/Asus/DFI/Giga-byte. MSI and ECS are *female dog* boards in my opinion. Never had one that worked correctly. Asus are good but their support kinda sucks.
Case - Whatever your preference is and what you're using it for. Some are tailored for cooling, other for ease of putting it together.
Monitor - No real bad company. Hell I still use monitors from 12 years ago, I will prolly never go LCD.
PSU - Thermaltake/Artec/Antec/Enermax (off the top of my head)
Drives - LiteOn/Asus/Sony/Samsung/ (doesn't matter for normal drives)
Like said in the CPU and GFx part all fanboys see everything differently. I've learned to stop arguing over which is the best, to each his own.