That most likely outcome the following map, where Obama wins every swing state, except North Carolina. This has been the 'most probable' Obama victory for some time.
Next up: Romney's most likely winning map -where he wins OH, VA, FL, NH, CO, and NV. This map coming to fruition would indicate a serious systematic bias in the polling against Romney. It's interesting that this map is more likely than a map where Romney wins just OH, VA, FL, and one of the smaller states - I interpret this to mean if Romney wins it's because there's been a systematic polling bias. If that has has been happening it's likely been happening in many states, not just the key states.
Next, here's the final histogram. Note that those 3 big spikes (332, 347, and 303 electoral votes for Obama) account for almost 50% of all outcomes.