well everyone is going to have there own opinion so i'll just put the ones that i watch and hope people give me more that are worth checking out. i'll give brief discriptions of the shows but remember that it is not everything the show has to offer just a brief discription.
Supernatural - About 2 demon fighting brothers who are very close and fight to save the world highly recommended if you are into demons and such, if you are religious....i dont recommend this show to you because it might piss you off a little bit.
Smallville - About superman before he became superman the life of clark kent in a different story then the comics very good show if you havent seen it yet i highly recommend it especially if you are a superman fan.
Gossip girl - The name of the show isnt very attractive to the ear but it is a pretty good show worth checking out its about a bunch of people most of who are rich going through colledge and parties and buying there way out of it as well as relationships between them and having there past catch up with them, hard to discribe but once again worth checking out.
Lost - About a group of people stranded on an Island trying to get off as the story unfolds it becomes very clear that weird shit is happening anouther highly recommended show.
Kyle XY - About a teen or adult clone not sure which that has been genetically enhanced to be a weopon but instead becomes a member of society and begins to discover What and who he is while the government is hunting him down. very good show worth watching and if you havent seen it its only on the first or second season if im not mistaken so it wont be hard to catch up.