Depends on the question. If it's something like, "Rank these items" your top choice should be 1. If it's, "How much do you like" it should be 10 as the best. I guess I see it as similar to the pain scale...1 is the weakest and 10 is the strongest.
I agree. The scale depends on A) what type of question you're asking and B) what quantity you're comparing. The question should make it clear which way the scale goes, or it's useless.
I also agree with Where's the Quiet's examples. You rank things starting with number 1 being the item that best meets the criteria of the question. You can tell it's a "ranking" question when every number must have an item associated with it (best=1, 2nd best=2...). You start from 1 and count down until you either run out of items to rank or arbitrarily cut of the list at a certain number (e.g. a "top 10" list). OTOH, if the question asks you to indicate where the magnitude of something falls between two extremes on a scale of 1-10, then 10 is generally the "strongest" or "largest" end of the scale (the "most" of the quantity considered = the largest number of points). In this case, it's not a question of "best," it's a question of the magnitude of some quantity. For example, if you're scoring pain on a scale of 1-10 where 10 is the strongest pain, then 10 is "most pain" (thing measured), but 1 is "best" (no pain). If you're scoring how well an athlete performs in the Olympics, then 10 is both "closest to perfect" (thing measured) and "best."