Personally, I keep it pretty simple, but I still try to look nice. I agree with the black thing...I wear mostly black clothing with maybe some other dark hues. And I tend to just make it up as I go. I'll wear random jewelry and accessories just for the hell of it. And I definitely wear random t-shirts some times. I don't really feel like I have much of a fashion niche because I just don't really pay much attention to fitting into a certain genre.
I tend to avoid heels though except during formal occasions.