1. Mayweather decision - By far the most likely outcome IMO.

2. Mayweather stoppage - Not a full on KO but maybe a late TKO or corner stoppage.

3. Pacquiao Decision - Most likely controversial if he gets a decision.

4. Draw - Which will most likely be controversial like all draws are and would lead to an even bigger and richer 2nd fight.

5. Pacquiao KO/TKO - Least likely due to Mayweathers defence, chin and ability to recover which is evident from all the other times he's been hurt.