notes on defensive alignments (edit)
I took a look at our favorite alignments in 2012 based on Pat's gamecharting (link above). This is charting through Stanford (excluding FSU).
Here's how it breaks down:
Overall
3-4-4 28% 4-2-5 25% 4-3-4 24% 3-3-5 14% 4-1-6 4% 3-2-6 3% Others 3%
Extra DBs?
4 DBs 53% 5 or 6 47%
Fronts?
3-man 45% 4-man 55%