I've got several kinds of basil started on the light shelf here, too. I pinch and harvest until August, then let them make seeds for next year. (I pick the seed heads, dry them, and rub them out of their little calicys -- calixes? pods? LOL.)
I'm going to harvest from just half my "Hot & Spicy" this year and let the rest start going to seed right away (well, I'll pinch a few times to branch them out) to be sure of having a good supply of seed to share for next year. This is a really great culinary variety that came from a friend of a friend of a friend... the packet was marked "Goree Island, Senegal." It has small, pointed leaves and tastes like Thai basil with a major peppery kick. Flowers are white, not especially showy, but bees still love them.
I've started some of the Italian basil a friend of mine smuggled back from Italy years ago, and another milder variety of Genovese basil, 'Martina' (fun bec. my neighbor and gardening friend is named Martina). I also started Mrs Burns' Lemon, Lime, Amethyst (purple leaf), and Holy Basil. I sowed Blue Spice, too, but it didn't germinate... have to look for a newer packet of seed (I've been saving this one for years, just grabbed the first pack I found and I bet it was an old one).
