Timeouts did not work for our oldest. He would constantly try to sneak or wrestle out of timeout and it turned into a game for him. We tried to stick with it but looking back I think it was a huge mistake and the contributed to behavioral problems he has today, basically full blown ODD.
If it seems like something is not working for you, don't try to force it.
If in doubt, love over punishment. Don't lose your temper.
This is where we're at too, the timeouts just don't work -- same behavior -- running out of his room etc. What I've found is to give him a little of something he wants (5 minutes of legos) before I need something (getting dressed for school). That way I'm not trying to force something "right away" and thus avoiding a confrontation in the first place. Once the power struggle begins, there's not really a smooth way out of it.
If it seems like something is not working for you, don't try to force it.
If in doubt, love over punishment. Don't lose your temper.