I shortened my putter down to 31" about 5 years ago. It got my eyes over the ball, got my arms hanging naturally and relaxed, and has definitely encouraged a straight-back straight-through stroke.
My putting has always been solid, but this seemed to move my distance-control up to a completely different level. I use a heavier mallet-style Ping putter, and I just really like the feel and the weighting.
It's all about finding what works and then sticking with it through thick and thin. If you're the type to lose faith after a couple of bad putting rounds - there's no stroke, grip, putting style that will help you. It just happens and you keep practicing and practicing til it happens less often.