It appears that another answer on this page was largely "inspired" by the Battlestar Galactica Viewing Order I created nearly four years ago.
That episode order was actually the first to take into account all the BSG extras, like the web series, deleted scenes, extended episodes, etc. It was also the first to suggest placement of Razor and The Plan in the positions mentioned in the other answer. There was no other such list on the internet at the time.
My list was (and still is) the first result in Google if you search for "Battlestar Galactica viewing order". Two months prior to the other answer being posted, it was so well known that it was even featured on an episode of TekZilla.
But clearly my blog didn't come up in the other answerer's research, because if it did, I'd like to think he would have given credit where it was due... Hmm.
Anyways, here's almost all of my original blogpost. (The original viewing order is even longer -- if you're looking for the most comprehensive and spoiler-free guide on the internet, I'd recommend checking it out: Battlestar Galactica Viewing Order (No spoilers!))
Battlestar Galactica Viewing Order
- 1.01 33
- 1.02 Water
- 1.03 Bastille Day
- 1.04 Act of Contrition
- 1.05 You Can't Go Home Again
- 1.06 Litmus
- 1.07 Six Degrees of Separation
- 1.08 Flesh and Bone
- 1.09 Tigh Me Up, Tigh Me Down
- 1.10 The Hand of God
- 1.11 Colonial Day
- 1.12 Kobol's Last Gleaming, Part I
- 1.13 Kobol's Last Gleaming, Part II
- 2.01 Scattered
- 2.02 Valley of Darkness
- 2.03 Fragged
- 2.04 Resistance
- 2.05 The Farm
- 2.06 Home, Part I
- 2.07 Home, Part II
- 2.08 Final Cut
- 2.09 Flight of the Phoenix
- 2.10 Pegasus (56 minute extended version)
- 2.11 Resurrection Ship, Part I
- 2.12 Resurrection Ship, Part II
- 2.13 Epiphanies
- 2.14 Black Market
- 2.15 Scar
- 2.16 Sacrifice
- 2.17 The Captain's Hand
Razor (101 minute extended version - not the 81 minute broadcast version)
TV movie. If you have this on DVD or Bluray, you have the extended version.
Important note: This was originally broadcast just before Season 4, but chronologically it fits here, telling more of the Pegasus's story. Some people argue it's better to watch after Season 3, as originally broadcast, but it makes most sense to watch it here. Read here for instructions on how to avoid the unintentional spoilers in Razor..
- Optional: Razor Flashbacks
Note: This was billed as a "seven episode web series", but really they are just deleted scenes from the shorter broadcast version of Razor. In fact, most of these scenes are now reintegrated into the extended version of Razor (the one on DVD and Bluray), making what's left even more unessential. (Read more about these deleted scenes here.)
- 2.18 Downloaded
- 2.19 Lay Down Your Burdens, Part I
- 2.20 Lay Down Your Burdens, Part II
A 10 episode web-based series bridging seasons 2 and 3. (25 mins.)
This should be included on your DVDs/Blurays, but if it's not, and you're in the US, you can watch it here.
- 3.01 Occupation
- 3.02 Precipice
- 3.03 Exodus, Part I
- 3.04 Exodus, Part II
- 3.05 Collaborators
- 3.06 Torn
- 3.07 A Measure of Salvation
- 3.08 Hero
- 3.09 Unfinished Business (70 minute extended version - Note: Not included on Region 2 DVDs, but is included on ALL Bluray releases.)
- 3.10 The Passage
- 3.11 The Eye of Jupiter
- 3.12 Rapture
- 3.13 Taking a Break From All Your Worries
- 3.14 The Woman King
- 3.15 A Day in the Life
- 3.16 Dirty Hands
- 3.17 Maelstrom
- 3.18 The Son Also Rises
- 3.19 Crossroads, Part I
- 3.20 Crossroads, Part II
Razor: Yes, this again. (Well this is where Razor was originally broadcast, after all.) Watch the last 10 minutes of Razor here. (Read here more information on what moments I'm talking about.)
- 4.01 He That Believeth In Me
- 4.02 Six of One
- 4.03 The Ties That Bind
- 4.04 Escape Velocity
- 4.05 The Road Less Traveled
- 4.06 Faith
- 4.07 Guess What's Coming to Dinner?
- 4.08 Sine Qua Non
- 4.09 The Hub
- 4.10 Revelations
Season 4 Continued (aka "Season 4.5" or "The Final Season")
- 4.11 Sometimes a Great Notion
The Face of the Enemy
A 10 episode web-based series (although it plays together like an intense mini-episode). (36 mins.) These episodes have not been included on any DVD or Bluray releases, but if you live in the US you can view them for free on Hulu.com.
- 4.12 A Disquiet Follows My Soul (53 minute extended version - only on Bluray releases)
- 4.13 The Oath
- 4.14 Blood on the Scales
- 4.15 No Exit
The Plan (DVD/Bluray movie)
A stand-alone movie that shows (approximately) the first two seasons from the Cylons' perspective. (You finally get to see "The Plan", mentioned all those times in the opening sequence!) Although The Plan was originally released after the show had finished, it is generally agreed that it should be watched here, so that everything is all tied up when you do reach the end.
- 4.16 Deadlock
- 4.17 Someone to Watch Over Me
- 4.18 Islanded In a Stream of Stars (62 minute extended version - only on BluRay releases)
- 4.19 Daybreak (150 minute extended version - only on BluRay releases)
The Plan : This is where this DVD/Bluray movie was originally released (after the show had finished). It seems universally agreed that it's preferable to watch this after No Exit, instead of after you've finished the entire series, but there's no harm in waiting until now.
An entire TV series set 58 years before the events of Battlestar Galactica, and revealing the events surrounding the creation of the Cylons. (Although it's worth noting that you don't have to have seen BSG to watch Caprica... and some people have decided to watch this series first, even though it was produced after BSG had finished.)
Blood and Chrome
This was potentially a whole new show at one stage, but it appears to be now just a stand-alone TV/web movie. The story follows the exploits of a young William Adama during the First Cylon War, and is considered a sequel to Caprica and a prequel to Battlestar Galactica.
As stated before, you can view this reading order in much more detail (and without spoilers) on my blog. Thanks.