I have HBO and really like it. I think they have some very good original programming: Entourage (though it may have jumped the shark by now), True Blood, Big Love, and to a lesser degree Hung. Also, I've become a boxing fan, and they often have good fights. Interestingly, I don't actually watch a ton of the movies, but that's largely because I've gotten into the bad habit of buying DVDs so I end up owning most of the movies.
For Showtime, Weeds is a really good show. I don't have a subscription to Showtime, but I buy that show on DVD. Don't know about their other shows, but I think I've heard that one of the others is quite good.
I'm sure other options are better and cheaper, but I'm kind of lazy with this kind of stuff. I like to be able to turn on the TV and have some options, particularly with a bunch of stuff avaialble via On Demand. Regular TV is just generally so freakin' bad.
