This reminds me of a Bart Simpson book where Bart outlines the ideal desk to sit at in his classroom: in middle, to the left or right, the spots the teacher looks least often.
Remember, if you're in the back, you might not be able to get away with as much as you might think: most teachers who give a rat's behind about classroom order scan the back of the class frequently.
Of course, if you're in college, the professor generally doesn't care what you're doing.
I sit at different spots depending on the class in question. My seating choice depends on a number of variables within each individual class, such as how quiet/loud the professor is, how boring the professor/class is, whether I might have a significant amount of free time during class I might need to kill, where my friends are sitting, and, yes, where any girls might be sitting.
[quote name='w00t_culafi']I sit behind of where the hot chicks are at[/quote]
Hey, if you have a chance to sit underneath the hot chicks, I'd take it.