I personally live off of cereals such as alpen, cornflakes, beans on toast and chicken and chips. Alpen and cornflakes being my morning meal. Not sure what you guys would make of the content of these, but they've worked well for me.
But if you're looking for the 'ideal' 10-15 mile breakfast, Machka is certainly right, you don't need to eat anything. I'd stick to what you eat already (if at all), I would only change my diet from what I enjoy eating if it was exceptionally long duration rides. However, even for 10-15 miles, it won't hurt to drink a little more water. As for the on-ride-snack, I have a mars bar but I don't ride long enough to actually benefit from a snack IMHO (2-4 hours).