A dyslectic friend refuses to read sans-serif fonts, because she can't follow the lines. Please do use serifed fonts, except maybe for short labels!

> However, it is also evident that they somewhat aid the horizontal movement of the eye along the printed line—the serifs at the top and bottom of a character create a “railroad track” for the eye to follow along the line of print. Therefore, when using a typeface without serifs, adequate spacing between the lines of print should be used in order to prevent the eye from bridging (slipping) to the adjoining line (Craig, 1980).

I like serif fonts, but on page 31 of that document, "List of Design Recommendations," it says: "Sans-serif fonts are usually more legible than fonts with serifs."