If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.
I admit this version of the question leaves substantial ambiguity that makes it harder to calculate an exact answer. I could have constructed a more well-defined version, but this is the version that I have been asking people already, and I'm curious how Less Wrongers would handle the ambiguity as well.
In the context of the question, it can perhaps be better defined as:
If you were in a situation where you had to choose between Truth (guaranteed additional information), or Happiness (guaranteed increased utility), and all that you know about this choice is the evidence that the two are somehow mutually exclusive, which option would you take?
It's interesting that you interpreted the question to mean all or none of the Truth/Happiness, rather than what I assumed most people would interpret the question as, which is a situation where you are given additional Truth/Happiness. The extremes are actually an interesting thought experiment in and of themselves. All the Truth would imply perfect information, while all the Happiness would imply maximum utility. It may not be possible for these two things to be completely mutually exclusive, so this form of the question may well just be illogical.
Defining happiness as "guaranteed increased utility" is questionable. It doesn't consider situations of blissful ignorance, where