I don't think we could have paranormal urban fantasy without the streetwise heroine – but of course that begs the question as to what makes a heroine "streetwise?"
For starters, even if she's not actually from the wrong side of the tracks, I think she has to be able to operate on that turf.
'Sexy' may make a fourth in here, too, but I don't think it's actually required in the job description...What's the jargon: 'desirable but not essential', he-he.
Maybe just a little bit badass, as well. But with a heart that's in the right place, even if it's in a "tough love" kind of way...
And if I go beyond paranormal urban stories, there's Tamora Pierce's Beka Cooper, Midori Synder's Jobber, and Kristin Cashore's Katsa.