Brothy soups with lots of vegetables . . . salads with as little dressing as possible . . . almost all low carb vegetables.
Any food with an ED of less than 1.5 per serving . . . preferably less than 1.0 if you can manage it. That is what I use when looking at pre-packaged food; like frozen dinners.
To calculate the ED simply divide calories by gram-weight. For example a frozen dinner containing 240 calories and weighing in at 225 grams has an Energy Density of 1.07 and is therefore very Volumetrically friendly. As another example take a look at some of those 100 calorie packs -- 100 calories for 19 grams of tidbits gives an ED of 5.26 -- obviuously not volumetrically good.
All this is pretty well explained in the book -- have you had a chance to read it?
And here we go for 2009 . . . Onward and Downward . . .