Nope, looking at houses is not suspicious, neither is looking at street signs, mail boxes etc--those are normal actions a person takes to find their way around.
Standing in the bushes looking in a house is suspicious.
We are so on edge in this country that we forget that we all have the freedom to walk down the street, look at what we want to look at, even stare at it for a bit if we want to. Any of us should be able to stand on public ground for hours and just watch the world go by if we want. As long as we aren't harassing anyone or impeding anyone's right to walk by then we aren't doing anything suspicious.
You are free to sit on a park bench and stare at every person walking by without fear of molestation by the police or your local neighborhood watch. Everyone of us should feel that we have that freedom regardless of our age, gender, color of skin or what we are wearing. The one fact that we all know in this case is that young Trayvon did not enjoy that freedom in his last minutes. He was pursued by Zimmerman without any cause that we know of--he did not enjoy the freedom to go where he wanted to go without fear or actual molestation by anyone. His death is a sad tragic event for everyone involved, but just as bad is the sad fact that large segments of our citizens cannot walk down the street with the same level of freedom enjoyed by everyone else.