Meusli, yum, yum! Like Roger, I learned to appreciate it while traveling in Europe. You could tell what country I was in by what I had for breakfast! In the Germanic/Nordic countries, it was meusli and yogurt. In France, of course, the ubiquitous pain au chocolat (chocolate croissant to you non-francophones).
I use the Bob's Red Mill meusli. It's a local Oregon firm, but the brand should be available in most of the US. I found some in a Kroger market (health food section) in Ohio 5 years ago. I add dried berries, but of course it's even better with fresh huckleberries in season!
For a change, I alternate meusli with Grapenuts cereal. I package each serving seperately in a sandwich bag with dried milk. Add water, stir, eat, lick spoon, put sandwich bag in garbage bag and I'm ready to go. I know the milk is a little messier, but it gives me a shot of protein and (at my age) badly needed calcium to start the day.
I have also been known to eat a Kashi cereal bar or two when I'm really in a hurry. I have to avoid most energy bars because they are fortified with every vitamin and mineral known to man, including iodine which gives me horrible rashes.