This only applies to people in the USA, and only people who aren't already subscribed to Netflix (well, it applies to existing subscribers too, except for the "free" part.)
For all my praising of On Demand -- and my love for On Demand grows like a weed, I have not done nearly enough to praise Netflix and its online streaming. There's a lot to like about Netflix even if you just like getting DVDs by mail. But its online service is really nice, too, and it doesn't cost anything extra. I worry in the future rates will go up, but for now, it as an extremely great deal at $8.99 per month (one DVD out at a time plus unlimited online streaming.)
If you have broadband Internet and you have an XBOX or PS3, and now, Wii too, especially if you have WiFi already set up it's a breeze to watch right on your TV.
Another bonus is Netflix's arrangement with Starz. I can't imagine Starz will want to stay in the deal as it is currently structured (I'm not sure how long the deal lasts), but you can get Starz movies and series, for cheaper than you can get Starz! For me to add Starz to my Comcast account is around $20 a month. Netflix is only $8.99. Sure, it's not in HD, but the quality is still decent.
And sure, Netflix doesn't have episodes from current seasons of most TV shows like the network sites and Hulu do, but it has past seasons in spades, even available for streaming. Try watching the first few seasons of Weeds on Hulu. Oh wait, you can't!
New episodes of Spartacus: Blood and Sand show up the day after they air on Starz -- perhaps sooner, I never checked.
You can sign up for a free trial of Netflix for one month and catch up on the existing 11 episodes of Spartacus: Blood and Sand. There are two more episodes to come in season one, but if you sign up now they'll be available within your free trial window. You can catch up on other Starz shows and movies, too.
P.S. No Netflix didn't pay me to do this post (I'm open to Netflix advertorial though!)
P.P.S. No Starz doesn't pay me to write about Spartacus: Blood and Sand (though if they want to give us a fat advertising deal for the season two premiere, I'm cool with it.)
P.P.P.S. No, the Netflix streaming numbers are not included in the ratings data posted for Spartacus: Blood and Sand