Let's get something straight, here: good discipline is not punishing a child when they do something wrong (more on this later). Good discipline is structuring your life so that your child learns how to live. Good discipline is not merely not-giving your child a biscuit every time they ask for one; good discipline is telling your kid what you expect of them before you go into the store and then giving them a hug when they do it. Discipline, after all, means "to teach"; it means teaching them to get up when they fall, to try again if they fail, that you--and by extension the world--have certain expectations of them that they have to meet in order to become members of society; that they can't always get their way and that crying about it won't solve problems. Good discipline, in other words, is a way of life, a mindset that you either embrace, or not. If you don't live a disciplined life, then no amount of time-outs or spanking will ever give you a disciplined child.
Punishing a child is something in the framework of good discipline, but it is not the end-all-be-all of discipline. It is something that needs to happen, occasionally, to teach a kid what not to do, but if you're disciplining your child then they'll have already figured out what they should be doing. You can't punish a child into good behavior. Bad behavior needs to have consequences, of course--but only insofar as it teaches the child what not to do. Teaching a child how to behave is not the same thing as smacking them until they stop doing anything. And spanking a child--well, like I said, I understand the urge to. But I'm an adult. I know better.
Which leads me to the other point: respect is not the same thing as fear. Respect goes two ways. If you respect your child's person--if you respect their wishes, stop tickling them when they say so, and respect them the way you want to be respected--then odds are they will respect you. This is not to say that you should bribe your child for good behavior, but just to say that children are people--or trying to be people--and the way to get respect is to give it. You can't tell a child "no TV" all the time while playing World of Warcraft for three hours straight and then expect them to listen to you when you tell them to eat their dinner. You can't tell a child it's not okay to hit his brother while spanking him for doing it.
And this is not to say that your kids will end up brats if you do these things or not. Kids are resilient and pick up a lot more than we give them credit for. As long as you're doing some kind of parenting, your kids will probably end up all right, despite everything you're doing or not-doing to screw them up.