I've been running Windows 7 for the past few months using the default Consolas font and in the past couple of days it seems to randomly turn ugly and blurry. Consider this from Visual Studio (I don't have Resharper installed):
I am running this on a monitor 24" monitor with a resolution of 1920x1200. However, a computer I have downstairs (I can't quite remember off the top of my head the resolution) with the same font seems to be in a permanent state of ugliness - even in Windows Explorer.
I ran the ClearType tuning tool on both systems numerous times with no change.