I understand openings of a glass allow for aroma to add to the taste. However I recently had Kwak in its recommended glass, which is similar to a test tube. I have seen a number of other unique glasses. Are these really only for asthetics or are these meant to add to the flavour?
Some brewers design glasses to enhance the experience of the beer in various ways.
IPAs in general benefit from a large opening to release as much aroma as possible, but there are other benefits.
I know Guinness in particular has designed a very special glass for their beer. The special glass features their golden harp, which you are supposed to aim for when pouring. This and the special curvatures of the glass help give the beer a good head and keep it until you're done with the beer. Stouts especially benefit from a silky, creamy head, so Guinness designed a glass around that.
I've never had Kwak, but from the looks of the glass it seems to be more of a branding effort than anything else. I can't imagine any potential benefits from a glass that shape.
This wikipedia article is a good read. It tells you what beer goes in what glass and why.
EDIT: Actually, the glass does serve a purpose. This site says the glass was invented for coachmen who weren't able to leave the horses and have some beer. The glass's peculiar shape allows it to be hung on the side of the coach for easy drinking.
Having the right shaped drinkware can improve the taste of beer. For example, there's very specific reasons for the shape of a weizen vase, or a pilsner.
However, more often than not unusual shaped glasses are about branding and nothing more. In this wikipedia article it is claimed that the fancy Kwak beer glasses (which I like incidentally) were not launched until the 1980s. IF that is true, their claim that it was designed for couchmen unable to leave their horses rings a bit hollow...
I do think that although the flavor of your beer is paramount, there's a lot more to how you enjoy your beer than 'just' flavor. Company, environment, and a beautiful glass or mug all contribute.