Are certain things *really* exceptions?

the above statement still has nothing that actually separates it from the fallacy known as Appeal to Common Belief

It does, actually. Scientific consensus is not the same as common belief . First, it is important to realize there are exceptions to virtually all informal fallacies (if not all). There is a point where reason is sacrificed for a strict logical interpretation—perhaps best articulated by "in principle but not in practice." The example I used was perhaps not the best, but not because it was fallacious but because it is too easy to find and understand strong evidence for the "old earth," where a reliance on expertise isn't necessary. But consider the thousands or perhaps millions of beliefs we reasonably hold based on a general trust of the scientific process. When our doctor gives us medicine, it isn't unreasonable to accept the belief that the medicine will work. When we fly on a plane, it isn't unreasonable to accept the belief that the plane is safe and won't crash. And when there are roughly 3% of scientists out there arguing that the earth is less than 10,000 years old, it isn't unreasonable to accept the fact that they are wrong based on the 97% who say they are dead wrong—without fully understanding all of the evidence.

For example, if a vast majority of scientists believe aliens exist somewhere in the universe...

Again, you are confusing common belief with findings of the scientific method. If these scientists hold personal, philosophical views it would be fallacious and fall under this fallacy to accept those views for that reason. It is important to differentiate between a scientist's personal view and a scientist communicating the results of scientific study. Reason is required here as well. Some issues are, for all practical purposes, "settled" (despite the fact that all scientific findings are provisional) and some are inconclusive (this is when there is no strong consensus).

even estimates of the age of the universe are changing all the time,

Be careful here you don't slip into the "science is constantly wrong therefore ignore it" camp. Scientific findings are constantly bringing us closer to the "truth" but rarely reverse course. For example, yes, estimates of the age of the earth are changing, but in no way are they close to 6000 years. They are changing within a few percentage points from the 4.5 billion years.

Bottom line: A scientific consensus is shorthand for scientific evidence. Accepting a scientific consensus is trusting the science more than you trust your own ability to accurately evaluate the preponderance of evidence on a given topic and come to an unbiased, conclusion. There is nothing unreasonable about this.

People seem to love the movie, The Shawshank Redemption.  In fact, it is currently ranked #1 at IMDB.com, based on viewer ratings.

This is a positive claim about the popularity of X, rather than a normative inference using X's popularity as a justification. The fallacy could be made a bit more clear though.

For example, if virtually all of earth scientists accept that the universe is approximately 13.7 billion years old, it is wise to believe them because they will be able to present objective and empirical evidence as to why they believe.

That last bit is important. We're trusting them not in-and-of themselves, but what they are very likely to bring to the table. A scientist would have studied existing literature - they might have even contributed to some of it - so they'd be in a position to know what they're talking about. Of course, the usual critical thinking skills still apply.