Good posture at work

I have recently completed a Health & Safety at work course, and although your fist reaction might be 'how dull..' there was actually some very interesting things to be learned. One of the major topics was concerned with the individual workspace particularly in an office environment where the type of office chair used can be very significant, but would apply to a factory worker or even classroom chairs and desks.
I discovered that if you use a PC for a significant part of the day, then because of the positioning and the inflexibility of layout, you should NOT be using a laptop as your main computer. This is something I, and I am sure many others are doing on a daily basis.
One of the first things I am going to insist on once our new H&S policy starts to roll out, is a new chair, a new desk and an independant USB keyboard for my laptop, and maybe even a separate screen too. It is surprising how much your seat, your desk and your desk layout can affect both your long-term health and your day-to-day performance.