I don't really have any must haves in terms of brands of products, but I do need certain types of products.
A really good detangling conditioner, otherwise combing out my hair is a miserable experience.
A moisturizing leave-in
Of all the types of products listed, I have about 2-4 of each that I know work really well with my hair. None of them are Deva products though. I've never tried that brand.