Shows similar to Mad Men in terms of plotting include The Sopranos (which has a similarly bleak and character-driven outlook, although a bit more meandering from what I've read) and HBO's The Wire (which offers a similarly microcosmic view of American culture and society during a particular era, albeit a more modern one).
Those are two that are "similar to Mad Men" in terms of some more thematic or narrative levels. In terms of shows that, like Mad Men, are extremely good, you have your usual suspects: Lost if you have patience for more questions than answers, Battlestar Galactica if you enjoy Science Fiction and Philosophical Questions, and if you're looking for a comedy series I'm in a period of suggesting How I Met Your Mother, an extremely high quality "sitcom" that has a real heart to it.
As for your enjoyment of House, if you're looking for high quality procedurals you can check out Pushing Daisies on the quirky and whimsical end of things - the show is getting canceled, but it's a real joy to watch and the first season is both a) awesome and b) available on DVD.
Hope this helps.
