My oldest never gave us any problems; she was four before she even had her first temper tantrum! My son - ASD - LOADS of behavioral problems that 'normal' techniques (time out, taking away things, etc) didn't help. Time and maturity was the true fix for much of his issues. Now, taking away privileges, things, etc. works with him. Then there is the 12 year old. She grew up in her brother's 'bad behavior' shadow. You'd think she would have figured out that no means no but . . . some kids are bullheaded. We take away things as consequences. None of our kids have a computer, tv or phone in their rooms; only the oldest (18) has a cell phone that she didn't get till she was 15 and got a job to pay for it. So things like ipods, DS games, computer, tv, movies, etc. are what get confiscated. Getting grounded too.
My youngest has a mouth and attitude on her. She's a terrific kid, very funny, but man -- the
attitude.

This morning she came downstairs looking in the dryer. I asked what she was looking for and all rolleyes, attitude, disrespectfully she says 'my capris'. Two warnings later she still wasn't getting it and as she slammed her feet (learned from her brother) up the stairs I promptly followed and took her DS. You'd think after umpteen times she'd get it. Backtalk gets soap in the mouth.
One more -- she got braces when she was 9 and just got them off in December (one week b/4 Christmas). She had to wear a daytime retainer (top only) all day and different nighttime retainers (one top, one bottom) at night for the first three months. It was repeated many, many times that the retainers could only be placed in their holders. Many times. We got to week five when she came home from school and said she forgot her retainer on the lunch tray and it got thrown out. Grrrr. $95 to replace. So . . . back to the store went her two DS games she had bought with birthday money. It covered 1/2 the replacement. Sometimes money is a good teacher. Sometimes not. She got the three months done with the daytime top retainer and . . . . lost the replacement!
We also reward good behavior with hugs and humor and verbal praise. Sometimes that backfires though and they get crabby. Kids!