In answer to the original question - is it heck! One of our national traits seems to be to run down our own country whilst praising others to the sky. I've even heard people who've never left these shores bemoaning the fact that they can't live "abroad", that mythical utopia. We try to get a London visit in every 18 months or so, settle on a certain area to explore, and wallow in what London has to offer. Last time we stayed in Greenwich, saw a concert at the O2, wandered around the superb market, cruised down the river, walked through the glorious park. We spent a few days in Kensington once, took in the museums - I could have spent days in the V & A! - went to the Royal Albert Hall (superb). For our wonderful Olympics trip we stayed on to do an East End pub crawl, St Paul's, the Tower, a scary Ripper tour. I could bore on for much longer, but will conclude by saying that we have travelled a lot, been to many iconic cities and loved them, but never been anywhere with the buzz, excitement, history and sheer number of things to do.
I agree that there's a lot of rubbish on the rails coming into the city, but we've found the streets are surprisingly clean, certainly better kept than many other British cities.