For defined, strong eyebrows I have never used anything other than Benefit's Brow Zing kit for the last 8 years.
Each kit comes with a tiny pair of slanted tweezers (which I always lose immediately) and two handy application brushes (again. they don't last long before becoming lost). The real pearl in this little oyster is the brow product; a pigmented wax for shaping and a shaded powder for setting.
I apply my brows by dipping a slanted brush in water before I apply it to the pallet so that the power is slightly wet before applying to my face. I just find it a more effective method for really structured brows. The powder is also very good as a natural, smokey eyeliner (again, when applied slightly wet).
I have just taken a quick photo (above) of how my structure my brows every day; as you can probably see, I love the bold, Elizabeth Taylor look. Its perhaps the most dramatic part of my face yet takes the smallest amount of effort or maintenance to do; we're talking two minutes to apply, it lasts all day and sweeps of easily with a bit of cleanser..