Only 2 machines in my house have the classic toggle switch on the back. The rest have the soft ACPI button on the front, and to power it down immediately you have to unplug it. Either that or hold the button and wait.
Dilgirl, if you have a desktop computer, you still have a computer with a power on/off button in the back...not that anyone ever seems to use it for anything.
I had a similar nostalgic moment to this recently at a friends house...I was looking at her parents books and found "Idiots guide to DOS" I pulled it out and it began with a short summary of how to turn your computer on that began something like:
"On the back of the computer, you should see a large red switch..."