World Devastator vs. Executor
One World Devastator (seen in Dark Enpire and the video game Rogue Squadron) vs. the Executor (Darth Vader's Super Star Destroyer, seen in ESB and ROTJ). I think this should be close, the World Devastator's were seen as more powerful than the Death Star, but that was all of them put together, not a single one. But a single one has proved very strong, destroying standard Star Destroyer's on it's own. So where I have no doubt that eitehr Death Star could take one out, what about the Executor?
vs.