I think bronzer use varies with each individual...I'm quite pale, so I use it to add a warm glow to my skin, and I use a darker, more matte one as a contour. I usually use a big fluffy brush and lightly dust over the areas the sun would naturally hit; tops of my cheekbones, forehead, nose, chin, and shoulders. For the contour I use the 109 brush (it fits nicely in all the areas that need contouring) and buff it in to the hollows of my cheeks, a bit near my temples and nose, and right under my jawline. I just got the Illamasqua bronzing duo and I'm in LOVE with it. the lighter side is a perfect bronzer for me, and the darker shade is an awesome contour color. They're both slightly shimmery, but not terribly so...I generally stay away from shimmery contours, but I don't even notice it once I put it on. They've got one for darker skin, and one more suited for lighter skin, though the light color is the same in both. HTH!
I'm already medium/tan, but I still wear bronzer to add a glow to my face. I really love Revlon's ColorStay Mineral Bronzer in Golden Bronze. I use golden bronzers rather then darker, brown bronzers because I feel like I get a more natural, sunkissed glow that way.
Plus, I feel like dark bronzers make brighter blush shades like peach or pink harder to show up on my cheeks, and I hate that.
I'm a tannish-brown girl (MAC C7/Px Antelope), but I can't go without bronzer. As soon as I even out my skintone with foundation, I look crazy (lol, I have a golden-olive complexion that kinda goes sallow sometimes). So I use bronzer and a highlighter to give my face "life". I use just a little bit and it makes a huge difference, if only to me lol.
My faves are Bobbi Brown matte and illuminating bronzers. Also Nars and Cargo. I use Nars' bronzer brush to apply (in a #3 shape motion on the face).
I'm NC30, with olive undertones.. Having foundation on alone makes me look sort of washed out/beige.. so I use brown with a big fluffy brush all over my face to add depth to my face and make me look more alive. Lately I've been using Sunny by Nature MSF, i love it.. and sometimes I use Matte Bronzer.. both by MAC.