9mm 147gr JHP in a Glock 19 with 1 extra magazine in case of failures.
Don't let anyone tell you 9x19mm is insufficient:
That is very smart. Lots of folks think that they do not need to carry an extra mag because 15 is plenty. 15 probably IS plenty, but the mag is the most common cause of failure for a semi-auto pistol, so it's smart to carry at least one backup.