Peter Boettke has a good post on the role of Hayek in the history of macroeconomics. He defends the idea that Hayek was Keynes's major rival in the 1930s and 1940s. This is certainly true, although I'm not sure that's really in question. Keynes really had two rivals - an academic intellectual rival (Hayek and the LSE group), and a professional intellectual rival (the Treasury). He and the Cambridge group overcame both by the end of this period.
Peter also makes arguments about the continuing influence of Hayek. He clearly made a mark on Hicks. Hicks is one of those guys that both Keynesians and Hayekians like, because he was legitimately influenced by both. Lucas talked about him too. I'm not quite sure this means that Hayek had a big impact on macroeconomics after the 1940s. The argument isn't that nobody ever cited Hayek after the 1940s, after all. It's that macroeconomics would have developed in much the same way without him. He wasn't a crucial player. The other thing to remember is that you can say pretty Hayekian things without relying on Hayek. I fully embrace the issues raised by the Lucas critique. This wasn't a battle for me - I was raised on Lucas critique insights. I fully accept a lot of Hayek too because I was brought up to think about the economy as an emergent order (actually - brought up to think that through a lot that Krugman wrote). That makes Hayek an important thinker to come back to. But has he really been a major player in post-1940 macroeconomics, or have their just been a lot of important congruences? I think these are two different claims.
I'm not well enough versed in the history to provide a definitive answer, but I think we need to be careful to separate "some people continue to cite Hayek, and we can see a lot of modern ideas in Hayek too" from "Hayek was instrumental in the development of modern macroeconomics". You can pick out Lucas critique type insights in Keynes too - he talks a lot about people's response to major policy changes, and it's very easy to draw Lucas critique type insights out of that. But I would never presume to assert - from that - that Keynes was critical to the development of the Lucas critique.