An interesting question. There are quite a few things that I don't care about the brand, but two things come to mind when I think of what I consistently purchase.

Music Samples: Getting into some more composition for media and videogames, I needed some high quality samples to trigger with media that didn't sound synthesized. I started by purchasing some from Spitfire Audio and kept getting packs from there. I think that part of it is loyalty to the company, but I know some of it is practicality. Since each new pack I'm looking at was recorded in the same hall, it makes it easy knowing that they will combine well together.

Shoes: It seems like I do have an affinity for the company Vans. I've tried other brands of shoes before and have purchased them, but I seem to always enjoy both the comfort and style of Vans for everyday wear.