Have you gotten a hatchery catalog (or two, or three) in the mail yet? I have. I'm already trying to decide what new layers I want to add to the flock this year. We've had great luck with Buff Orpingtons, Barred Rocks, and Plymouth Rocks. Rhode Island Reds, too. Our climate is cold, so we go with the heavy layers - and they did make it through our 30 below zero night last week with just a 60-watt light bulb for heat.
Speckled Sussex are a less common breed from England. We've had three of them, and they've been very friendly, curious and intelligent birds. But their feet didn't hold up well through our frigid winters, and they've lost toes to frostbite. They don't seem to mind, and they are still able to roost (although we do have some more "accessible" roosts that used to be nest boxes for the one whose feet are in worst shape - they're easier for her to perch on). So we'll skip them from now on, but if you're in a warmer clime, they are fun.
Want more guidance and inspiration for picking your new baby chicks? Check out Build Your Flock for some guidelines and tips.