That's a tough question to answer.
I think United will beat AC Milan he they're at their attacking best. But Chelsea vs. Liverpool... I have no clue who will win! I'd give the slight nod to Chelsea just because their deep pockets tend to squeeze out important wins. How many injury time goals have we seen then get this season after one of their high priced bench warmers came on and had a moment of brilliance?
United and Chelsea in the final and it's very fitting since the FA Cup and Premier League Title will go to either one. The two best teams in the world it's safe to say.
I'll pick United.