Definitely, the info should be for the unit size/volume. Also alcohol should have the label as well. People should know how many calories are in their drinks.

The serving size can be relevant (whos going to drink an entire large bottle of V8 all at one time?) but there's no reason they can't do a side-by-side comparitive thing, similar to how cereal boxes compare the stats for the cereal by itself (dry) and with milk.