This question can seen to be quite ridiculous since Cambridge is mainly highly ranked as a whole university in all international rankings.

But rankings are not the main factor I take into account and, moreover, it is not always easy to compare US & UK LLMS.

I have been offered a place at Duke and at Cambridge.

I also received two prestigious scholarships for Duke and a full scholarship (totally unknow and awarded by my home university) for Cambridge.

The courses available at Duke seem to be more interesting according to my projets.

I want to study a mix of securities regulation, corporate law and IP if possible.

For those who are aware of the content of the LLM at Cambridge, the course list has been shortened for the coming academic year.

I wonder if I could find what I want seeing that there is a very limited amount of courses that will be given at Cambridge in 2010-2011.

Do you think it will be a "bad" choice to prefer Duke over Cambridge ?

I will not go into the modules issue 'cause it's without a doubt a very important thing to consider when making a decision and it seems you've got the reputation thing all figured out. I'll focus on the fact that you've been awarded a full scholarship to Cambridge. Even if it's an ''unknown'' scholarship (in comparison with the famous ones you've got from Duke), it is, nevertheless, a full scholarship. The fact that you got one is something that will stand out in your CV, regardless of whether it's a famous one or not. And considering you can never save enough money, in my humble opinion that alone would already be enough to take Cambridge up on their offer and toss Duke aside. After all, I might not be very acquainted with the modules available on the Cambridge LLM, but I reckon there is a fair variety of modules for you to choose from for the area youre interested in (I ended up talking about the modules issue... sorry!)

Excuse me, but where did you get the information about the courses in Cambridge in 2010-11? Their homepage only lists the courses offered in 2009-10, which are pretty much the same as in previous years.

Here is a link to the provisional list of papers for 2010-2011 at Cambridge:
http://www.law.cam.ac.uk/faculty-resources/summary/llm-papers-to-be-offered-in-the-2010-11-academic-year-provisional/6864

As for the choice between Duke and Cam, I'd definitely choose Cam, unless prestige really doesn't matter for you. You'd probably have more fun at Duke and I agree that the US system is more appealing than the British one.
I don't think that getting a prestigious scholarship is such an important factor (unless it is the Fulbright), especially since you have a scholarship for Cambridge.

Good luck deciding.

Indeed, one of my two scholarships is Fulbright. The scholarship for Cambridge has been awarded by my home university, not by Cambridge.

Is the prestige of Fulbright above the prestige of Cam ?

Hmm, tough one. Fulbright is after all the most prestigious scholarship in the world (well, maybe the Rhodes is more/equally prestigious in the Commonwealth).

It kind of depends on what you want to do after the LLM. If you are going to go back to your home country (which the Fulbright requires you to do), you should ask around about your options' relative prestige.

Congratulations on having an enviable dilemma!

First of all, thanks for the link.
I don't know if it helps, but a colleague of mine did his LL.M. at Duke. Following the rankings, it is without doubt a good university, but the city of Durham (USA) itself seems to be pretty lame. So I don't think you'd necessarily have more fun there.

Edit: Oh, and in my home country (Germany), Fulbright of course is a reputable scholarship, but it's not necessarily considered to be more prestigious than the other ones (at least that would be new to me, and I think I have got some insight into these questions as far as Germany is concerned). In fact, many people don't even apply because you can only give preferences and thus don't have full control over the university you are put into.

However, I totally agree that is quite disappointing that there will be no "Corporate Finance" Course in Cambridge this year (nor any other Finance/Capital Markets Law related course).

I don't think it would be a bad decision at all. You may want to consider where you are from and where you hope your LL.M. will take you.