Which area to stay in London for 3 days?

Anyplace in Central London would be fine.

I walked past the Holiday Inns in Kensington and they looked nice, in a very nice area. I loved walking around that neighborhood with my son to Hyde Park. The Forum is kind of a high rise building. Would need to take the tube to Big Ben, Westminster Abbey but that is easy once you learn to navigate the tube. Id consider a Big Bus tour first day unless you already know London. The Marriot Grovsner looks nice also.

If you have points with Holiday Inn then my very best recommendation is the Holiday Inn in Bloomsbury. Good area, very central, all the transport systems ( tube, bus and mainline rail stations ) are very close by. All the major tourist spots are very close at hand.

p.s. excellent pubs as well, particularly the Lord John Russell on Marchmont Street.

If you have Marriott points then the most central and grandest location is a no-brainer...London County Hall. The London Eye is just outside your window. You have a view of the Thames with Big Ben smack dab in the middle. Westminister Tube station is just across the bridge.

Premier Travel Inn is also located in the London County Hall building on the end opposite the Marriott. PTI is about 1/2 price of Marriott - you just can't find a more central location and having points is just a huge plus!

If you can get the Marriots County Hall with your points disregard my earlier comments about Kensington and stay at the County Hall. Can walk easily to Westminster Abbey, Big Ben and not too far to St Pauls and Trafalgar Square. I stayed at the Premier Travel Inn County Hall and forgot there is a Marriots there. It is just an incredible location. Nice to just walk out of your hotel and sit on the Thames and watch the Eye.

I agree with the previous posters. I stayed in South Kensington last summer. Nice, but we tubed every day to Westminster since the area was mostly residential. County Hall will be a very convenient central spot especially for a shorter trip.