Inconsolata - http://www.levien.com/type/myfonts/inconsolata.html - I won't work on in any IDE without first making this the default. It is incredibly worth of consistently being considered among the best programming fonts (http://hivelogic.com/articles/top-10-programming-fonts).

Of the fonts that are widely compatible on the web, I like Georgia and I especially like Palatino - it's way under-rated. Both are serif fonts.