While looking over my collection of brushes, I realized that I've got a really small collection of brushes for the cheek area. Nothing wrong with that, since I use these four 95% of the time!
MAC 129 ($35) Old faithful. It’s the standard blush brush that works for all occasions. I’ve used it for over ten years with no complains.
MAC 116 ($35) This is a flatter blush brush, so it lays the powder directly on my skin. Bobbi Brown said to do apply blush by starting at the cheek bone and to pull the brush down toward the hollows of the cheek. Once I started doing that, blush looked totally different! This brush really helps with that effect.
MAC 165 ($35) This particular brush is domed and pointed, so it works well for a few reasons. If you use the tip of the brush, it’s wonderful for adding a powder highlight to the cheek. If you use the side, it’s slim enough to highlight around the eye and along the cheek bone.
Real Techniques 300 ($24) This blush is flatter than the 116, more firm, and it looks like I paid over $100 for it. I use this similarly to the MAC 116 above. I'm always scared that it'll get stained, but it never seems to!