Sorry, haven't watched it yet - I can't view these things at my place of work, I'll watch it when I get hime (if I remember!).
Argentina has little hope of winning - they barely made it to the world cup - if I recall, they had a tight playoff with Uruguay and just scraped in. Mexico also has little hope. The US might suprise a few people and get right up there, although I doubt they'll actually win it.
You'd have to put your money on Brasil. The hosts have been playing very poorly lately, as have England, and I don't know if the rest have what it takes to beat Brasil right now. There should be a few very tightly contested matches though, can't wait till it starts....