I'm not sure what you mean by computer brand. The CPU, the Graphics card, the Mother Board, etc. Most Computers sold by brands have parts from other companies. Intel processors are best for office work while AMD processors are best for gaming. So, I have no favorite in terms of processors. For Graphics cards, NVIDIA and RADEON are great. For Mobos, AMD or ASUS will do fine.
For laptops, ASUS and Toshiba are the best. They are sturdy and also performs well.
I hate HP - expensive, buggy and easily breaks down. By all means avoid this brand.(I also don't like Acer - too mediocre)