I wouldn't say it's unhealthy. I usually go with the Rice Chex if I will be sharing. There's no gluten in that and I have a couple friends avoiding it. I've made it without Chex cereal. You can use Cheerios or any of the other low fat, low sugar cereals too.
Some add-ins are nuts, coconut, raisins, dried fruit, or carob chips. I just throw things in that seem to go well together. I take some in a little container to work sometimes. Like trail mix, it gives a little energy boost in the middle of the day as long as you don't sit and eat it all day long.