For a snack with decent neutrient balance i love Myoplex Lite, they taste wonderful too. 180 calories.
For meal replacements when spacing out calorie intake (mid morning, mid afternoon) i like Cliff bars and Promax bars. Promax Fudge is the chocolate lovers dream bar. 260 calories for cliff bars, 350 or so for Promax.
For protein supplement, well, almost all bars are loaded with some sugar or pseudo sugars which i hate the taste of, so i just try to drink protein shakes instead. If you must most any of them with moderate carbs and a mix of casien and whey will do. Muscle Milk was gonna make a bar but i have yet to see any.