If you're looking for some smaller, sometimes more exotic type planes, Van Nuys is a host of some very interesting aircraft. There are two main places where you can take photos, and just driving around the airport itself you can find little spots here and there.
The corner of the street there has a fence, but there's also a wooden post where you can stand on and get above the fence. I've had police drive by and just look at me, but never question me. Also, on the exact opposite side of the runway from there, (by the way, this is best viewing for 16R/L operations), http://maps.google.com/maps?f=q&sour...0.001003,0.002411&t=h&z=19&iwloc=A
is an actual viewing place. I believe it's open from sun up to sun down, but I've been there during the dark and the police just ask you to kindly leave. Van Nuys is my favorite airport in the world, and I wouldn't look away from it too quickly.