A new challenger in the coding font wars appears; Luculent. (See this discussion on HackerNews for more fun).
For the record, I still think Consolas is not only a great-looking coding font, but is also the best-engineered one in existence. Having said, that Luculent is charming and quirky and cool. It's at least worth a try on your dev box.
Let's explore some specific sizes. All screenshots below were done with text in Notepad on Windows 8.1. The source code come from here.
Luculent 11pt
Luculent 10 point
Luculent 9pt
Luculent 8pt
Luculent 7pt
Now some if the problems become obvious.
Consolas 7pt
I Look Consolas it handles the same text at 7 pt below.
Comparison
A PDF with detailed comparisons is available here: http://1drv.ms/1cM24Wh