In an attempt to find a font that would allow a spreadsheet to be legible, I took an old .xls that had a string of all the letters & numbers duplicated in many cells, but with each cell in different fonts (all fonts size 10). This sheet is invaluable
for quickly finding a font that makes a particular letter look good.(For example, B1 would be formatted in Arial; B2 would be formatted in Tahoma, both with the same character string.)
In Excel 2010 (32 bit) on Win 7 HP Pavillion G6 1366x768 display, the different fonts were all visibly different at zoom level 80%. But dropping the zoom to 78% caused most normal fonts to suddenly look identical (and fuzzy). Yet some fonts, eg wingdings, still looked unique. I need a font that looks good at 70% zoom, and presents legible text, not icons. Converting the sheet to xlsx made no difference.