I have very little to do with this thread since I'm studying law at ucl and have virtually no knowledge of the respective quality of ICL and Kings' med schools. However, I can dispense some advice as to their location. Kings' med school is, as you probably know already, located on the South Bank, next to Waterloo - nothing particularly wrong with that but it cannot plausibly stand the challange against Imperial - located in one of the most charming neighbourhoods in london - south kensington - some of the accommodation are literally across the road from the new main entrance and the various departments are pleasently set amidst charming squares, leafy parks and elegant houses. The main london meseums are at your doorstep: Natural History; V&A; Science Museum and so on. In addition, Fulham and Kings road, probably the two most popular streets in south london, are both within easy reach. If I were in your shoes I wouldn't hesitate - the choice would seem ominously evident to me. And, irrespective of the quality of the specific departments, Imperial's overall reputation is considerably stronger than Kings.
Hope this was of any help.