With the risk of being unpopular I have to admit I have found what I've read of Popper to be seriously overrated. So far I have gone through The Open Society... and the better part of The Logic of Scientific Discovery.

Open Society to me read mostly like a critique of the political philosophy of Plato, Hegel and Marx, with brief mentions of what the open society is actually supposed to be (I recall some mentions of social engineering and other such things). At best it felt like a grounding for the currently dominant neo-liberal social order.

The Logic... on the other hand does seem to bring novel content, but I feel the core of his endeavor is hopeless. Science definitely doesn't and can't work in a perfectly coherent algorithmic way. Science is a human social process that can't be subjected to a strict methodology. On this front I think Lakatos or even Kuhn are much closer to how things can/do work.