You may also be looking for a way to change the results of "edit top 200 rows" which now (to me) seems to be two or three pixels smaller than it used to -- probably my eyes:)
Note that the text editor, the most obvious choice, and the one that used to control this, no longer controls this in SQL 2005+ - it just controls it in New Query window
Use Tools/Options select environment/fonts and colors then use the drop-down to select Data Viewer. Then pick your font, say OK and restart.
Apparently there's no way to separate the "editor" portion (above) from the results (below) (although you can scroll the size using your Ctrl/ mouse wheel, it does not "stick" after a submit)
They both need to be in the same font (Bad Microsoft! Bad! No desert for you!)