The draft is more noticable with a bigger vehicle (like a rented moving truck), but I can notice it even in my sedan just by the slight change in wind noise and the gas pedal position needed to maintain speed (manual transmission and excellent throttle response).

I follow closely sometimes, but not for the purpose of drafting, just to keep from being cut off or to get around someone slow. Tailgating someone rarely gets them to move out of the left lane at 55mph on the highway. If there's no chance or benefit of passing (residential, two-lane road, speed limit under 40mph, etc) then I see no reason to follow closely.

If you're staring at the bumper in front of you, following close is stupid. You have to look much further ahead and adjust your following distance based on the visibility both in front and from the sides. I drive on the left side of the lane so I can see around the cars in front of me (or look through their windows ahead of them). Watch for brake lights of the cars ahead too.