Roosters are good at sounding alarms. Very few of them are good protectors, though there are exceptions.
Attacking people is common, but most roosters don't. I'd avoid hormonal production breeds such as any type of production red (ISAs, Production Reds, Red Stars), and hatchery Barred Rocks (There are people who say that no breed of rooster is more aggressive than any another breed. My experience is the opposite).
Some roosters are naturally better with hens than other roosters, too.
If you're inexperienced with chickens, I wouldn't recommend raising a boy from a chick. They tend to do better when raised around other roosters, and by experienced chicken keepers.
If you do get a rooster, I'd get an adult rooster from someone who hatches out chicks and raises them, and is maybe looking to retire a flock rooster, or has a promising cockerel.