That's ironic as most non US citizens convert their money into US dollars before going to Cuba and use US dollars when there.
IIRC, the Cuban Convertible Peso is actually pegged with the US Dollar.
What I ultimately think will happen to Cuba is the same thing that happened in China and Vietnam. Once Fidel Castro dies, the country will go through significant economic and social reforms. Ultimately, it will remain a single party state, but will only be communist on paper. Raul Castro has already been making some movement on reforms. Though he is still heavily influenced by his brother.
The problem with Cuba right now is its dependence on Venezuela for many staples goods. Oil in particular. With Chavez dead, the Bolivarian Revolution movement is starting to collapse. Venezuela has turned into a banana republic, and simply can't afford to be shipping heavily subsidized oil to its allies for much longer. China owns a lot of their debt and Beijing is a fickle mistress. So if Venezuela defaults on its loans or the United Socialist Party loses power, Cuba loses their primary economic partner. This is similar to what happened in the 1990s when the Soviet Union collapsed and Russia stopped giving foreign aid. The country underwent a major economic downturn.
For Cuba, its going to have to convert a big chunk of its economy into a tourism based one like other Caribbean nations. Right now they do have a sizeable industry. Mostly Canadians and Europeans. The fact that its a tropical paradise that's only a short flight/sail away from the US makes it very tempting. These islands don't have enough natural resources to exploit to make anything else really viable.
From the American perspective, they're waiting for Castro to die as well. I think that's the crux of the embargo. They don't want to deal with a man who almost brought the world to nuclear war just so he could wave his dick around at the gringos. American hotel and cruise chains are probably itching to establish themselves there. The big European ones, notably Riu and Melia, have already carved a nice little niche there.