Different components have different fans and therefore the following is only my opinion.
PSU's: Seasonic and Cosair are my favorites. Other people like Antec but I am not a fan.
Memory: Crucial has treated me very well over many years. OCZ, Patriot has as well. Corsair, PNY, GSkill I have also used... Its not like these companies actually make the ram chips.. well except for Crucial. LoL
HDD: I normally only use Western Digital but lately I have been using Samsung without issues.
Motherboards: Here i look more for user reviews, because everyone makes a bad board, being careful to weed out bad reports from people who just dont seem to know what they are doing or give a bad report because it doesnt have a feature they thought it would/should. I avoid ECS at all costs. Gigabyte and Asus are my top 2 followed by MSI and Biostar for non-server builds. I certainly would not hesitate to use an ASRock or Intel board if the reviews were good and it had the features I want.
GPU: XFX, Sapphire, MSI, Gigabyte, Asus... Again I'm looking at reviews of specific cards and reading forums at how well the company is supporting their users.
Cases: I look for the features I want not any specific maker. I note reviews for any peculiarities and wether they would affect me or not.