Deadwood is a 3 season TV series produced by HBO, with a gritty and realistic western setting. (do not confuse this with Torchwood!)
Top class acting / directing / script as you would expect from HBO. (Tim Van Patten and many other HBO regulars write and direct episodes of this series)
If you like westerns and you have not seen this series you are making a big mistake. Similarly if you enjoyed the Wire or the Sopranos, or any other big HBO series you will also like this too!