Skip London. My last time there was for an extended period. I did everything from pub crawl to hit exclusive restaurants. As a whole, I found the Brits to be less than friendly, about half insulting in their humor towards Americans and just generally not much fun. Quite frankly, the best part of the trip was hanging in an Irish bar. Ireland, on the other hand, was full of warm and friendly people. I was wearing boots and a Stetson and I don't recall ever paying for a drink (from what I can recall at all!). The people are just good as gold. Don't talk religion or politics.
Seriously, you cannot help but love the Irish.
Id rather go to Germany but the people I'm going with are going to Germany after I have to come home. They are continuing on to Amsterdam, Germany and Spain.