Going to London? Give the Marriott Maida Vale a chance. It's a four star hotel located on a bus line that gets you into central London in about 15 minutes. It's also about a half-hour walk away from Abbey Road Studio and that famous zebra crossing.
Good food, fine breakfast, very nice rooms and a top-flight staff, full of helpful tourist tips.
And, no, I don't work for Marriott. I was just really pleased with them when we stayed in August of 2007.