All the dramatic series I have watched in order of goodness (keep in mind these are every series i have watched completely, not counting sitcoms):
1. Six Feet Under (5 seasons, concluded)
The best show I have ever seen. Pretty much constantly amazing throughout the entire series.
2. Sopranos (6-7 seasons concluded)
Great show, became a little tired during the middle seasons but came back super strong with season 5 and on. Season 2 is probably the best.
3. Lost (5 seasons, concluding 6th season about to begin)
Very strong during seasons 1 and 2, then a little weak, its been back strong with season 5.
4. 24 (7 seasons not concluded)
You expect a show like this on network television to be terrible but its basically awesome, and remained awesome all the way into the 6th season. The 7th season was incredibly weak however, and the new season appears to grow out of it so I am not optimistic.
5. House (5 seasons currently running)
Once again I was skeptical of a network medical drama, but this show cares a lot about the characters and doesn't really have any glaring flaws, its just really entertaining.
6. Dexter (4 seasons not concluded)
This show is not without flaws. The constant spoonfed voiceover narration and the campy concept kind of annoy me, but the show has been JUST good enough to keep me watching it. The new season with John Lithgow was quite awesome though.
7. Oz (6 seasons concluded)
Oz is also flawed, but you have to give them more credit than other shows because they basically originated the pay-cable serial drama. Very entertaining show, and every season is consistently pretty good.
8. True Blood (2 seasons, not concluded)
I loathe the whole vampire pop culture with all my heart, and I only watched this show because it was written by Alan Ball (Six Feet Under and American Beauty). It however sucks a dick. It has its moments, but basically it sucks a dick.
9. Breaking bad (2 seasons, not concluded)
Season 1 was great, Season 2 a massive disappointment.
10. Prison Break (4-5 seasons concluded)
Worst show I have ever seen in my life. The first couple of seasons were ok, and pot-committed me to watching the last 2. Stay far away from this piece of shit.