A sans-serif font like Arial, IMHO, is a poor choice for most maps, simply because 'sans-serif' is more difficult to read (on a map) than any serif font. (Serifs being the little tails and end-objects at the ends of the letters. (For a research paper, as a wall of text on white, I can put up with sans-serif, but even then prefer Verdana, because some letters like capital "I" has serifs.) While I might not try a different font on every map like Ascension, since there are thousands and thousands of fonts to choose from why not be experimental or find some flavored font that especially fits a given theme for a map. There are numerous Celtic fonts, some more readable than others. I might use an exotic font like Elric, but only for a main title and not for individual labels, as Elric is very difficult to read beyond short titles. For most of my Kaidan maps, I want a slightly exotic, oriental font, but most oriental fonts look 'cheap' to me, so I've been using AucoinExBold. This font while not officially oriental the curves on the strokes as well as the serifs have a distinctly oriental brush style yet doesn't look like a cheap Chinese Restaurant menu font.

I do carefully choose my fonts for maps everytime, though.