I wouldn't recommend using the NARS Illuminator as a bronzer. A product that I think that you would like much better that would give you a natural-looking tan is Bobbi Brown's Bronzing Powder. This bronzing powder is formulated with the perfect balance of red and brown tones (that exist in a true tan) to give you the most natural effect. It blends perfectly with all skin tones for a sun-kissed glow and the buildable formula allows for a "deep tan" look. You can take a look at it here: http://www.sephora.com/browse/product.jhtml?id=P27
If you prefer a shimmery finish, it comes in Bobbi Brown Illuminating Bronzing Powder which you can find here: http://www.sephora.com/browse/product.jhtml?id=P27
I hope this helps you.
I use the NARS illuminator (in orgasm though, not laguna), and it makes a night and day difference for me. I just put a little on my cheekbones under my foundation, and it is just enough to add a healthy glow, even on days when I'm feeling a little under the weather or just didn't have time to do my usual makeup routine. I probably wouldn't use it as a bronzer though as it quite "sparkly" (I only use very little on my cheekbones). Have you tried Smashbox Fusion Soft Lights in Baked Starburst? It has a similar luminizing effect (for me at least), but is better for an all over color since it's not as sparkly. Hope this helps!
Unless you have very dry skin I wouldn't use this as a bronzer for your face, at least not in the typical areas. This product has a lot of shimmer to it and will definitely give you quite a glow.
You can add a touch of it to your foundation to darken it a tad and give your skin more luminosity but as I said before if you have oily skin or skin that tends to shine on its own I would skip it.
I think this is gorgeous as a highlighter though for your cupid's bow, browbone, top of cheekbones, collarbone, down the front of your shinbone etc.
I hope this helps!