House is the great equalizer. Everyone loves House, from all age groups, all interests, never seen an exception. And, there's 6 seasons, so it will last you a while. Watch House, and you will be doing yourself a favor.
Another thing to add here is a bit of an underdog: Castle. Firefly is an obvious choice because it's quite simply really good, but mainly because it has insurmountable geek cred. And a major reason for that is none other then the great Nathan Fillion. The man is impossible not to like. And Castle is a show about him playing a mystery writer who teams up with a cop as research for his books, and they end up being a pretty good team. Yes, it's hardly void of cliches, and has some cheese factor to it, but that just ends up making it accessible. It may not be realistic, but manages to be ostensibly so, and the characters are all very likable. Its worth giving a shot, its on Hulu.
Also, as a runner up, and speaking of Joss Whedon, there's Dollhouse. It gets a mix bag of reviews, but if she's into Sci Fi, it's a show that has stuff to appeal to both typical gender tastes. Beginning is a bit slow, picks up in the middle of season 1, and then gets really good in season 2. Ive also seen it convert a few girls who are pretty meh about sci fi, so it's also worth a trip to Hulu.
