Battlestar Galactica is definitely recommended. It's actually quite dark and nothing like the original series.
Deadwood was awesome (still waiting for that finale!!)
I'd also highly recommend Carnivale even though it was cancelled after two seasons.
I watched one season of 24 and that was enough for me. I've never even seen the sopranos yet...
I do have the first season of Firefly on my 'puter though but for now I'm hooked on Battlestar
