Hi,
For shows currently airing, (in no order of preference):
24 (BBC2)
ER (E4)
Third Watch (Channel 4)
Law And Order: Special Victims Unit (Hallmark)
CSI: Crime Scene Investigations (Channel 5)
For shows, in general, again in no order of preference:
Law And Order: Special Victims Unit (Hallmark)
Oz (E4 and Channel 4)
CSI: Crime Scene Investigations (Channel 5)
Third Watch (Channel 4)
The Practice (BBC Choice)
As you can see, I'm rather partial to a) US dramas, and b) crime and legal dramas (of one kind or another).
Pooch