Do different beer glass shapes really make a difference in taste? I understand the basic distinction for wine glasses: red wine glasses are shaped to help keep some of the aroma inside the glass, whereas whites don't. But shapes for beer glasses, such as pilsner vs a standard pint glass, just seem to be an aesthetic difference. Yet I've had people insist that glasses make a big difference for things like Belgian beer. 

Is there a sound reason to use the "right" glass for each kind of beer?
Yes.  Taste is really smell, and different glasses can capture aromas differently.  Furthermore, different aromas may be more or less present dependent upon temperature, and a glass may be crafted to be held a particular way (gathering more or less heat from your hand).  The same is true for wine glasses.

That said, how much of a difference it makes to you is what's important.  Going back to the wine comparison, I can sometimes tell the difference between different glasses, but not consistently.  So it's not the most important thing.

Now that that's said, there has been some informal, perhaps less than perfectly scientific studies, including a blind test.  Beer advocate provides some more detailed information.  Some of my local bars carry stemware for specific European beers, and I know of one stateside brewery, Black Shirt Brewing in Denver, which really wants you to stick your nose up in it (to good effect, in my experience).