It depends on how you define atheism and agnosticism. Usually agnosticism is nothing more than what one might consider a soft version of atheism. I only accept proposition (1), not both (1) and (2). That is, in an important sense, suspending judgment with respect to the existence of God. I call myself an agnostic to dissociate myself from a certain hard-headed brand of atheism because I think it's unjustified. You can call me an atheist if you want, but I think whatever sort of atheism I can be said to adhere to comes to basically the same thing as agnosticism.
edit: plus I take issue with the idea that there is or can be knowledge regarding these matters. There is, however, an asymmetry between the various relevant propositions. For instance, I do not think there is knowledge of God's existence at this time, but I don't think that it is logically impossible for there to be such knowledge. On the other hand, I do not think there is knowledge of God's nonexistence at this time and I also think that in principle there never can be such knowledge.