The weird person that I am, I am compiling a spreadsheet of different types of food and their nutritional value so that I can get a better idea of what's available for me, and I've done cereal already! Basically, granola seems to be better in general to have for breakfast, it generally has the lowest carb content per 100g. The Dorset Cereal's granola is good, as long as you avoid the ones with dried fruit in. I also eat the Jordan's Country Crisp, although it has more carbs than the Dorset. There is an extremely low carb granola from the Paleo Food company, but it is a) really expensive, and b) high in fat due to the coconut in it! Steer away from anything with dried fruit in, as it bumps up the sugar content. I try and aim for anything under 60g carbs per 100g. Also, try to stick to the recommended portion size too. For the first few weeks I hated it because all my cereal had disappeared, but I got used to it.
In the week, I tend to have bacon and egg because they do it in our staff canteen and it's easier than bringing in cereal and milk. I normally have one slice of wholemeal toast with it, or a wholemeal roll. Eggs are good for you so they're good to have in any form really (less fried the better tho). I made egg muffins once and they were actually really nice - there are loads of recipes available for them online and they last a day or two after making. I only make two at a time because I'm the only one that eats them, but you can do that with just two eggs and a few ingredients, like cheese, some onion, little bacon, whatever you like. Lovely low carb breakfast.