Craig Ballantyne always posts good workouts and interesting articles on his website, Tubulence Training Fat Loss. Recently, he posted something guaranteed to irritate old-school gym rats, 10 Exercises to STOP Doing. They are:
#1 – Lunges without perfect form
#2 – Anything done with a rounded back (even picking up dumbbells)
#3 – Bench dips (where your hands are placed on the bench behind you)
#4 – “Clean and Presses” done with a fixed bar
#5 – Squats where your knees bend first
#6 – Narrow Grip Upright Row
#7 – Side bends
#8 – Plyometrics to Failure
#9 – Russian twists
#10 – Sit-ups and Crunches
I'm pretty much in agreement with Craig on this. With the exception of sometimes succumbing to the strange siren song of crunches, I don't do any of these exercises. I'm particularly glad he mentioned the Bodybuilder Bench Press and Bench Dips (where your hands are placed on the bench behind you). Almost every single weight lifter I know has at one point or another had some sort of serious shoulder issue, and I think these two exercises—esp. the Bodybuilder Bench Press—are major contributors to shoulder injury.
I highly recommend taking a look at Craig's article.