I thought that starting around Easter was a good time to start (provided I don't slack, of course) and would allow me plenty of time to revise all the content, practice with past papers etc. so I'm prepared for the exams.
I read this thread and the fact that most of you are starting to revise ridiculously early makes me feel like a failure.
Then again, for 2 of my subjects (Travel & Tourism and Leisure Studies) we don't even start learning the exam unit content until March. So that only leaves Sociology and GCSE Spanish as the subjects I'll start to properly revise at Easter.