Sopranos still holds up, but it's a lot less novel then when it premiered. I think people liked it so much cause it had naked titties and they said "fuck" and people got popped in the head. You didn't see that a lot in TV shows back in 1999, but it's really commonplace now.
If you watch Sopranos, just stop after the season three finale. It's all downhill from there. For the love of god, avoid the "movie" that came out last year at all costs.
LOST is one of the biggest wastes of time ever imposed on a mass audience. The writers insisted that it was all gonna make sense and they had a plan all along, but they were lying through their fucking weasel teeth. Every week they just made up more shit and flung it like apes at a zoo, seeing what would stick to the wall. None of it makes any fucking sense, none of the mysteries are answered in any logical or satisfying ways, a vast majority of the mysteries are just plain abandoned, none of the continuity makes any sense or fits together. It is an absolute waste of fucking time and I wish I could have all those hours of my life back. I'll never subject myself to that horseshit nonsense again.
Mad Men sucks too. It's hand down the most boring and slow TV drama I've ever subjected myself to, call cause "critics" ranted and raved about how "amazing" it was. It wasn't. It had ONE great character, Don Draper, and every time he wasn't onscreen it was like watching paint dry. Peggy Olsen is ugly as shit and almost as annoying. All the supporting characters are boring as fuck. I will never understand why TV critics collectively jizzed themselves over this boring ass, lame TV show for dead people.