For a few years now, I've preferred Google Maps over other map sites, for its ease of use. Recently though, Multimap made big improvements in its ease of use, putting it on a par with Google. It also has better street maps, and high resolution aerial photography.
At about the same time, Google launched a feature "my maps" which allows you to annotate maps. Just in the past couple of weeks, they've added high resolution satellite photography of (as far as I can see) all of Lewes District. It's such high resolution that I can tell it was taken before we removed a small yucca tree from our garden!
shows the site of Lewes Library, before it was built. Can you see any other clues that date the satellite imagery? It looks to me that these images were taken during a working day, but which year?