I went to the FoWA conference in February 2007 which was on just off Kensington High Street. The best value in the area seemed to be via www.london-discount-hotel.com who got me a room for three nights for STG174GBP incl breakfast in the Quality Crown Hotel.
I arrived in Heathrow and accidentally headed for the tube instead of the Express. This turned out to be a stroke of luck as I took the Picadilly line (slowly) to Earls Court. A short woalk up Earls Court Rd, turn right onto Cromwell Rd and I was at the hotel in a few short minutes.
The hotel itself is mid-sized and reasonably modern. They call themselves a designer "style" hotel. This is another way of daying "tiny rooms". It was difficult to turn in the room it was so small. However it had a fine bed and was very clean and air conditioned. Wired internet worked fine and was approx STG10 per day. I think I only had to pay for one day. The included breakfast was actually quite expansive and the staff were friendly.
The walk to Kensington High St took less than 10 minutes and was a straight line to the Town Hall where the conference was on.
As long as you are not too tall and have no real need of a big room, this hotel is highly recommended. Note however that whilst Voddafone has a perfect signal on the first floor, O2 has almost none!. .... Read Original Full Review.