My favourite makeup brand would have to be Maybelleine for budget beauty and Benefit for more expensive items. These are brands that I would happily use their products solely, even though I choose not to. I think Maybelleine have a great range of foundations, blushers, lipsticks and glosses.
Benefit is my 'luxury' makeup brand. It isn't THAT expensive, but to me it is. I love their products, especially their mascara, eyeliner and eyeshadows! They also do amazing blushers and bronzers!