Only stayed in London twice - the first was at the Park Lane Hotel - that was nice, the staff were incredible. The room was okay, not very nice on the furnishing side, but we were rarely in the room anyway. I disliked the shower because the curtain kept sticking to me! I hate when that happens. Other than that, it was a really good place to stay.
Second time we stayed at the Sheraton Park Tower in Knightsbridge. It was VERY VERY nice. We got one of the executive rooms on the higher floors and we were looking straight into Harvey Nichols every morning watching them prepare food type stuff. The bed was SO comfortable and no problem with the shower this time as it was huge and had a glass door. There was a separate bath that was big and deep and good for washing clothes that had gotten hugely dirty during the London marathon (not that I was running, I was just getting dirty watching!). Wasn't too keen on the staff (especially the big burly bouncer types later in the evening) but overall it was such a beautiful room that it definitely topped Park Lane (which, my fiance loves to point out, is NOT located on Park Lane - he went about changing all the "Park Lane" labeled things to "PICCADILLY").
Yorkshire - Lion's Inn at Blakey. Hugely recommended, not only for the food, but for the quaint suites they have available for overnight stays. Beautiful scenery, freezing cold, and the perfect place to get away for a romantic weekend.