While “Rome” has garnered great critical praise and respectable ratings, it hasn’t yet become a “water cooler” show. The same with “The Wire.” I’ve seen both shows and they’re very well written and acted, but I don’t feel any compulsion to watch them, and neither strikes me as innovative. Many of the older shows also seem to be losing their luster. “Curb Your Enthusiasm” had a so-so year at best. The inspired intersection of seemingly random occurrences that fueled the best episodes of the earlier seasons was largely missing. And the first half of “The Sopranos” final season was a let down. Perhaps it was all a setup for a whiz-bang grand finale, but too much time was spent on the growing pains of Tony’s son, AJ. There were still some great moments, no doubt, but overall things were flat. From what I can tell, the only HBO show generating any buzz at this point is “Entourage,” and as much as I like the show, I’m not certain that the buzz is actually real. It sometimes seems more like a product of the HBO hype machine than a reality. How many people do you know who actually watch the show?

Now I’m not tolling the death knell for HBO by a long shot, because the network is still home to great original movies, like “Hot Springs” and “Elizabeth I,” and non-fiction series like “Real Sports with Bryant Gumble,” “Inside the NFL,” “Real Time with Bill Maher,” and several shows with Bob Costas (though in my opinion, Costas seems better suited to ensemble work now that his youthful, virtuostic intelligence has fermented into frequent preening and grandstanding with age), but lately they seem to have run out of gas in developing new programming.

On the other hand, ShowTime seems finally have come into its own in developing series after a rocky start. The network’s initial forays into series were underwhelming. “Queer as Folk” was certainly groundbreaking for its depiction of gay sex, but overall it was really a pretty tepid melodrama that managed to divide the entire gay universe—aside from the main characters—into one of three stock groups: elite snobs, drug-addled party boys, or humorless PC do-gooders. The “L Word” is essentially the same show with better supporting players. I watched “Queer as Folk” consistently, but often wondered why, and I held out little hope that ShowTime would ever create an original series truly worth watching.

Then along came a little show called “Weeds.” On paper the premise sounds like a desperate bid to manufacture buzz by being provocative: widowed suburban mom becomes a pot dealer to maintain her affluent lifestyle. But in execution there's nothing heavy-handed—no sense of trying too hard—about the series. In fact there’s something almost magical about the show’s tone and the way that it effortlessly seesaws between biting comedy and earned drama. Certainly a lot of the credit goes to the writers, but it’s the ensemble cast, led by the luminous Mary-Louise Parker, Elizabeth Perkins, Romany Malco, Justin Kirk, Tonye Patano, and (believe it or not) Kevin Nealon, that gives the show its special alchemy. “Weeds” has quickly become one of those shows that I truly can’t wait to watch each week, and if I miss the first run I get depressed, even though I can watch it the next day on On Demand.

ShowTime followed up the success of “Weeds” with “Huff” and “Fat Actress,” starring Kirstie Alley. “Huff” leaves me cold for some reason, though the critics and Emmy voters seem to love it. “Fat Actress” was admittedly uneven and derivative of “Curb Your Ethusiasm” (and Kirstie screwed up the whole premise by selling her soul to Jenny Craig), but it was evidence that the network was trying and it gave me hope that “Weeds” wasn’t just a fluke.

This season that hope has been proven justified with the introduction of “Dexter,” starring Michael C. Hall. Again, on paper the premise seems a bit desperate: Dexter is a forensics investigator for the Miami police who uses his skills to track down serial killers...whom he then kills because he’s also a serial killer who was taught to harness his killer instincts by his foster father, a cop. Yes, it sounds a bit goofy, but the show really works. The writing is crisp, well plotted and insightful, the pacing is brisk, and the acting is exceptional.

On the few occasions when I watched “Six Feet Under,” I found Michael C. Hall bland and a little creepy. As Dexter, however, those qualities work in his favor. Watching him navigate his way in the “straight world,” pretending to feel like everyone around him while masking his sociopathic impulses is fascinating. The show also gives Hall a chance to show an unexpectedly deft skill with dark humor.

The supporting cast is equally good, and includes actors from some of my favorite other series: Lauren Velez (“Oz”), David Zayas (“Oz”), James Remar (“Sex and the City”), Julie Benz (“Buffy” and “Angel”), Jennifer Carpenter and Erik King. It’s fun to see the familiar faces get to stretch by playing parts that are the exact opposite of the roles that I previously enjoyed.

It may be a little soon to declare that ShowTime is the new home of must-see series (especially since "Masters of Horror" has been such a disappointment), but they’re certainly headed in the right direction. And if you don’t want to shell out the bucks for yet another premium channel, rent the DVDs. The one advantage of the short seasons on ShowTime is that you can watch an entire one in 6–8 hours.