Honestly? I always go back to the core MS fonts (Arial, Courier New, Times New Roman, etc...). I even use the Fixedsys typeface when coding. They're usable, familiar, and most importantly, look good at small sizes.
The downside is that an unusual renderings (e.g. Font size 17), they don't look great, but it's a small price to pay.
This view seems to have fallen to the wayside, but I vehemently prefer rasterized / bitmapped fonts. Every type of font smoothing looks blurry to me and causes eye strain. Of course, very few modern fonts look good without smoothing - only a few of the old standbys (Arial, etc...) have usable bitmapped versions.
While Linux handles this fine, Windows requires replacing Segoe UI at the registry level in order to fully change over.
I recall reading a similar clinical trial involving bacterial vaginosis. In BV, vaginal bacteria are imbalanced and thus it was hypothesized that transplanting healthy flora would be helpful.
The downside is that an unusual renderings (e.g. Font size 17), they don't look great, but it's a small price to pay.