go for Wimdows 7 unless you actually want a touchscreen . It's a very good system, you should get a good deal and be able to haggle for an even better price. Ask for best price, look at what is available on line (so you know what the computer is worth when you go into the store) and then ask for laptop bag (if you go for a laptop) and discounts for Microsoft office. If you opt for extended warranty ask for an extra discount for this too. Don't ask and you won't get. Salesmen desperately need to sell, remember that . Don't forget to get anti virus for free or half price and ask for the best system they have. I have great fun haggling for stuff.....in my element esp when the salesman initially says he cannot drop his prices.
i think Apple macs are grossly overpriced. I have an ipad....it's excellent but not without its glitches. I pay for an IPhone (but own a Nokia ) which is excellent too but is no better than other cheaper phones.
microsoft will still service Wimdows 7 for few years yet. Decide too on what specs you want in your computer and possibly which brand. This makes it easier to compare prices
Good luck KEF. Enjoy the haggling.