I have tried the M&S baked crisps- they taste like cardboard BUT they have salt and vinegar flavour corn snacks in the count on us range that are lovely. I also nibble on their salt and pepper pretzels and always keep some in my drawer at work for overtime hunger pangs.
If you're a crisps and dip while watching TV person a weightwatching friend of mine makes homemade salsa (I have a recipe if you want it although I don't think shop salsa is very high in fat)and toasts pitta bread and then cuts it into crisp sized bits. Very tasty and more filling than crisps...