I agree with what Gonzo said...your question is open ended for answers and there are a number of threads in search on the subject. That being said...bottomline...because of the wet clutch...energy conserving is not good (with the star shaped emblem) because of friction modifiers. This is usually 30 weight and below.
Top choices, after six+ years on the X watching what other people use...synthetic is Amsoil, Mobile 1 or Rotella as the top choices. For dino...all over the map from Honda, car oils, and general motorcycle oil.
Bottomline...change often seems to be the key for long life. How often is another one of those open ended questions...like religion...can have many viewpoints. I think it really boils down to how often and the climate one rides in. 3-4K seems to be the general consensus on dino and 8-10K on synthetic. Now, for sure, there are guys that go longer on dino because the book says so...their bike and their call. It has been difficult to prove engine failure do to oil...albeit I have read few and far between piston failures that could, the operative word could, be do to oil or it could be to lugging the bike.
Good luck eitherway...lots of threads, how to, and video on oil changes...now don't ask me about oil filters...another one of those no right answer questions.