I think some of the "addictiveness" is learned. I've found that when I've been eating healthy, faithfully, for a couple weeks, I start to crave healthier foods, and my desire for things like french fries and potato chips fades away. But if I eat the old junk foods again, the old cravings will come back again for days.
Edit 2011-05-25: At the request of @Ivo Filpse I've added some information about why I recommend these foods. I've also linked the foods to ShopWell.com so that people can easily view their nutritional content. I am not affiliated with ShopWell.com in any way. I just find their site useful.
Some healthy snacks that I really like:
- Applesauce. I recommend the unsweetened, all-natural variety. Yeah, it has some carbs and sugar, but it's about 1/3 the calories of ice cream and is almost as satisfying. 1 cup of unsweetened applesauce has about 120 calories, 4 grams of fiber, and 60% of the recommended daily allowance of vitamin C. It is also very low sodium.
- Watermelon. Watermelon is very low calorie by weight/volume, due to being mostly water. 1 cup of watermelon balls has only 46 calories, 21% of the RDC of vitamin C, almost no sodium at all, no fat, no cholesterol, and 1 gram of fiber.
- Popcorn. This is one of the least healthy options on this list, but it's still a lot better than potato chips, and it might satisfy the "chip" craving. Popcorn is a "whole grain", high in fiber, and low in cholesterol. How much fat and sodium it has depends a lot on which variety you choose. There are healthier and less healthy options. I can't eat popcorn without some kind of seasoning, but to minimize the impact to your diet, try to avoid trans-fats like "partially hydrogenated oil" and varieties that have a lot of butter. Air popped is better than microwave.
- String Cheese. This is a high protein option. One stick of the linked string cheese has only 70 calories, yet 8 grams of protein. That's 45% of the calories from protein! There is some fat and cholesterol (as with any dairy product), but it's not too bad. This isn't a low sodium option so watch that you don't go overboard (but again, not nearly as bad as potato chips).
- Grapes. Grapes are higher sugar, and higher calorie, than watermelon or applesauce, but are still a pretty healthy choice. 110 calories per cup, they're full of vitamins, especially vitamin C. No fat or cholesterol. Almost no sodium.
- Peanuts. Peanuts are high fat, so eat them in moderation. But eating 160 calories (1oz) of peanuts is a lot better for you than 1oz of potato chips. They're fairly high in protein, and a good source of fiber. No cholesterol. Lots of vitamins. Raw, unsalted peanuts have almost no sodium, but since you're probably going to want to eat them salted, you will end up with some sodium. Still, a lot better than potato chips. Peanuts can really fill you up and leave you feeling satisfied, where potato chips would have you feeling sluggish and craving more in a couple hours.
- Triscuit crackers. Simple, natural, ingredients. Whole grain. High fiber. A good source of Iron. Not necessarily a low calorie option, and definitely not a low-carb one, but you're getting a lot more for those carbs than other salty snacks would give you. Eat them with tuna fish and/or cheese for a light meal! (Incidentally, Tuna is an awesome source of protein and other nutrients, although I don't really consider it a "snack")
- Greek yogurt. This is a high protein option. About 40% of the calories from protein! And you can get even healthier by choosing a "vanilla" or "honey" flavor, although honestly I really don't like the non-fruit varieties. Blueberry's my favorite. Greek yogurt has no fat and no cholesterol, and low sodium. It's a great source of calcium. And like all yogurt, the live cultures have a positive effect on your digestive system.
- Oatmeal High fiber. Pretty decent protein content. No cholesterol. Low fat. Good source of iron. Whole grain. No sodium whatsoever. This is an excellent, excellent choice unless you need to avoid carbs for some reason. Most people will add some kind of sweetener, but it needn't spoil the nutritional value if you go easy. I recommend raisins and a tiny bit of sugar and cinnamon.