Recommend a TV show!

Okay, so I'm looking to (slowly) increase my library of DVDs, specifically TV shows. All the television I get at home is what I see on DVD, so I'm looking for recommendations from my LJ friends. You guys have similar tastes, or at least tastes that overlap with mine. :)

Here's the kind of thing I like:

-drama
-crime/detection
-fantasy
-science fiction

Basically it has to be fiction (I am not a fan of reality shows, news shows, etc. I like documentaries but not enough to own most of them). I am looking for well-written, well-paced shows. Plot and characterization is key. :)

So. Recommendations?

:::ETA:::

The show need not be current, but it does need to be available on DVD.