I've tried a lot of different glasses for sipping spirits neat, and this is my personal favorite. I suppose for some individual spirits there might be unique glasses which might do a slightly better job, but for a single glass, that can work excellently on multiple spirits, I would be hard pressed to find one better than this one. The problem however is that it isn't readily available.
The glass is made by Kusak Crystal (http://www.kusak.com/) here in Seattle. They don't mention it on their website, and they don't sell it online. The glass came about in an effort to create a "scotch whisky" glass for "Hop Scotch", a now defunct restaurnat/bar here in Seattle that specialized in Scotch. The owner of Hop Scotch, and the owner of Kusak Crystal, sketched up some ideas on a napkin, and had the glasses made by a glass manufacturer that Kusak worked with in the Czech Republic. They sold the glasses at Hop Scotch, where I bought some, and then when Hop Scotch closed down, I bought a bunch from the owner himself.
There is a VERY similar (actually too similar for coincidence) glass available from "Bottege del Vino", and available online here: http://www.cheftools.com/Bottega-del-Vino-Crystal-Johnsons-Whisky-Tot-Set-of-2/productinfo/03-0161+++02/
The glasses from Kusak cost me I think $10 apiece while the Bottega glasses are $40 apiece.