Early "Retirement"?

I'm currently enjoying my work and not too stressed out, but I can see a time in 2-3 years when I'll have been working for the same company for ten years, and with my 8 weeks "long service leave" then becoming fully vested, I could consider making another career change.

My first career, straight out of uni, was as a research scientist working on minerals processing equipment (with a bit of computer modelling and computer systems admin thrown in). This made good use of my first degree (in Applied Chem) but I actually found the programming of more interest than the chemistry (although playing around with the analytical equipment was a fun way to make a living).

After ten years my first employer laid off a large portion of the research staff in a cost-cutting drive, so I took the chance to change career into the "real world" of a private business-services company, and make use of my GradDip in Industrial Math & Computing. After taking an initial pay cut to get my foot in the door, I soon was earning more than in my old job, and had opportunity to progress up the "management ladder". But after 8 years I'm thinking of what I want to do for the next 20 years or so.

I'm currently half-way through a Masters in IT by distance ed, and I've just been accepted into a Post-Grad Diploma of Secondary Education course for next year. The plan is to finish of the MIT and the GradDipEd in the next couple of years, and then get put on the waiting list for a High School science teaching position. If I nominate only schools in the area we live (Sydney Northern Beaches) the waiting time for a position will be quite long (although they seem a bit short on Science teachers), so I probably wouldn't get a position immediately.

The plan is to accept a suitable teaching position (which will mean a pay cut of 50% or so), and treat the new job as a sort of "early retirement". The change of career should make the job interesting (at least for a decade or so), and the daily hours and amount of annual leave entitlement should make the hourly rate similar to what I currently earn - sort of like changing to a part-time job ;)

I'm sure any teacher's out there will say that teaching is anything but a part-time job, but, at least on paper, it looks like a good idea.

What do you think?