I'm gonna be happy, really happy, when it comes out. I'll play it and be glad for it. As it stands, not really hyped - I only get hyped when it's a fruitless hope, for some reason. Such as hoping that TF2's End of the Line will bring me weapons.
But seriously - judging from what I've seen, the Re-Logic team have poured their heart and soul into this to make Terraria a better, more balanced, deeper, expository and hopefully innuendo-packed game.
I can't decide whether to look at the changelog or not - with Terraria, I think it might be better to, since I will do better knowing what I should invest time into. However, my perspective was recently changed by a playthrough of Spiral Knights, which I got on a whim (mostly for the TF2 hat) and had immense fun playing with little or no help from the wiki.