Since you saw the snake and didn't immediately have a negative reaction, but instead asked yourself what you should feel, I think it says a lot about how you are aware, and conscious of your choices. In our culture snakes have been labeled evil as you well know, which points to duality of good and evil, choice. However, I would suspect the reason snakes were considered evil and used as a symbol in the story of Adam/Eve may have it's roots in primal associations of the snake of bigger proportions than a grass-garden snake (yet garden itself in this regard brings up Garden of Eden association again).
I've been asking myself this very question recently as well. In terms of Kundalini why the snake, if it can be deemed evil, then why does it relate to higher consciousness. Well, I think snake is just a symbol in this case because of it's movement, back and forth like how a snake slithers, and that's what the Kundalini does, it's a flow of energy. It's not really a snake, the kundalini, it's just the snake's movement resembles the energy movement. I would also suspect that since a snake is labeled a "lowly" creature as it is bound to the ground, the symbolism of it rising up relates to consciousness rising from the ground up to a higher plane.
It's also interesting the snake was black and white in your dream, again this is the duality, good/evil, choice question right there.
I'd also have to reacquaint myself with the moses staff being thrown down and turned into a snake and what that means.
I suspect snakes were viewed as a symbol for life. Like the staff of hermes/mercury with two snakes ascending in the DNA cycle - that's a clear symbol of life. Where there is DNA, life and thus consciousness exists. I think snakes have been given a bad-rap with people applying a one-sided view of what their symbolism means, but they go much deeper than that. I think they represent the fabric of life itself, they have life, movement, desire, will, and make decisions, although basic instinctual ones, I do think they represent a kind of evolution of consciousness born from the earth, rooted in the world with the potential to ascend to higher consciousness.
Remember, hermes/mercury is messenger of the gods, his symbol is the staff with two snakes (caduceus), and is used as a symbol of the healthcare field.