For the balance of young, ok prices, nicer areas I was thinking shoreditch, Hoxton and farringdon. A lot of development going on there to make it into the Silicon Valley of the uk.
Lots of tech start ups, google investment in young tech professionals and an area to match. It's a good part of London with good transport links to east and west, although probably about 50mins on the overground but you get to look outside
plus a route straight through the centre if you can bare the cramming in peak and cold days.
Definitely a younger area with the nightlife geared up. Perhaps a little pretentious but a lot of places are in London.
Take walking shoes, you can walk surprisingly far, some great buildings, download a tube app, bring a winter coat and try to walk off the main streets as there are plenty of hidden gems. Tell your wife not to leave her handbag on the floor in bars and restaurants in central London tourist spots, hook it onto the chair legs and keep it zipped there and on the underground.
If I need to stay over I usually book with an app called hotel tonight but it does limit your choice a little.