There are so many options for you, depending upon your intentions. When you say "good investment", in MY mind, that means that you want to get lots of EGGS to eat or sell. If that's the case, there are some breeds (like leghorns or production reds and a handful of others) that will begin laying earlier than most other breeds, and will reliably lay one egg a day, for 6 or 7 days a week.
Or you may mean that you want a naturally sustainable flock to save money by not having to purchase new chicks every year or so. In that case, you will want to get at least one rooster (cockerel), and choose at least one or two pullets that have motherly instincts (in chicken terms, we say, "hens that go broody"). These hens will occasionally decide that it's time to sit on and incubate eggs (instead of setting them and forgetting them like production breeds do). These same hens will often raise and care for ALL of the chicks they hatch (even when they came from different mothers)!
Personally, for ME, a good investment means having an all-girl flock that has some variety. That makes it easy to tell them apart (and name them, which my daughters love to do). It also gives me a variety of naturally colored eggs, which makes for a personal touch when I give my neighbors eggs on occasion! Those are the kinds of "investments" that have intangible dividends.
Either way, I encourage you to take the leap and learn as you go. You came to a great place for that!
