An old saying in martial arts self-defense is that you should keep your punches up and your kicks down. That is, don’t kick above the waist. Like most rules, this one has some exceptions.
For example, if you’re flexible and quick, there’s no reason not to follow a blitz with a roundhouse to the head. In keeping with the above rule however, I’d say at least avoid leading with a high kick.
If you want to follow the rule strictly, here are two great kicks for the street.