Now, let us contemplate who was OMITTED from the image:
#1 Tory Foster - as one of the hidden Final Five we have to assume she plays no part in the ending of the story, so she is likely killed before they get to Earth - possibly by Tyrol as revenge for Callie's murder
#2 Baby Hera - the female child of Sharon and Helo
#3 Baby Nicholas - the male child of Tyrol and Callie - possibly killed by Tyrol
#4 Gaeta - the braniac and officious C&C officer, and now singer
#5 Dualla - the empathetic, soulful, loyal soldier - interesting theory on Dualla as the Final Cylon: http://www.cellounge.com/2008/04/27/the-final-cylon-will-be-revealed-now/
#6 Romo - the all-too-clever Lawyer from Baltar's trial
Who is NOT the Final Cylon:
#1 Romo - You do not introduce a primary character in the Third Act
#2 Adama* - It would elicit groans from the audience if they would be so unimaginative as to pick Bill Adama as the final Cylon. He has been the rock upon which the others have relied. *It would make no sense except for the fact that the Leoben named him as a Cylon.
#3 Kara - She is the most flawed of all the major characters (except perhaps Baltar) and thus the most human - it would be a contradiction in terms to make her the Final Cylon - further, her story arc is half of the 'star-crossed lovers' and by definition she cannot be the same as her lover
#4 Lee - The younger Adama is the voice of conscience for the humans
#5 Helo - Hera is not important as a "Hybrid child" if Helo is a Cylon - and he's a dull character, so it would be a letdown
#6 Ellen Tigh - Her story arc is essentially over, except for Saul Tigh projecting her image onto Caprica Six
#7 Billy - He's dead, as in really dead
#8 Admiral Cain - Michelle Forbes will not be back, sorry kids
#9 Doc Cottle - Are you kidding?
#10 Callie - You did just see her flash-frozen in space
Who MIGHT be the Final Cylon:
#4 Daniel 'Bulldog' Novacek - only if they pull a Dr. Daystrom out-of-a-hat
#3 Tom Zarek - a curveball choice, but not a good one since his character has been so weasely
#2 Dualla - Evidently she shares family ties with the Adamas in the Caprica series so that greatly boosts her chances, and from a 6.5.8 Zap3It interview, Jamie Bamber had this to say about Dualla, "Lee now lives on Colonial One and she lives on Galactica, but there’s a big Dualla story coming up that will answer all your questions before the end." Hmmmm
#1 Felix Gaeta - The strongest of the misdirection choices - but his character lacks the heft, yet he was strongly teased in the Guess What's Coming to Dinner episode - he sings now which Final Five Cylon Anders thinks is important and Leoben did say, "The unstruck music vibrates within us all, few can hear it." Well, Gaeta is singing it.
The FINAL CYLON:
This leaves only two characters with the heft to be the Final Cylon: Roslin or Baltar.It only makes sense that the Final Cylon would be at the heart of the action all along, not at the periphery. Why the Final Cylon's self-knowledge would be triggered last bears some serious explaining. Roslin is the obvious choice, for she has been the Earth Mother to her flock all along, and the writers have foreshadowed her character twice - she's felt something in her head prior to Cylon attacks. Baltar is the more interesting choice, given his craven self-obsession. If the show ends at an Earth which could give rise to the ancient Greek God structure referenced in the story (circa 1500 B.C. in the eastern Mediterranean), that would favor Baltar - for he could be the equivalent to Zeus, a seriously venal and capricious god. The writers have been throwing Jesus references around in the story of late, which I sincerely hope is just misdirection for if they decide upon that as an ending - ugh, it will suck. It would violate their own trap they've devised for themselves with the endless "all of this has happened before and all it will happen again," refrains. The end would be the beginning, and the beginning had the Greek God structure of the Twelve Colonies and Kobol.
Roslin or Baltar.
(Be sure to see post on Galactica Variants "Final Cylon Must Be Roslin or Baltar")
An excellent article over at SpaceWesterns http://www.spacewesterns.com/articles/60/
offers theories on the Last Supper image. Terrific analysis by N.E. Lilly & Galactica Sitrep's Logan Gawain [Lilly seems convinced that it is Kara who is the Final Cylon]. One vital fact most of the thoughtful suggestions seem to omit is the central Six. Remember, she is the first Cylon we met. Also remember that the Cylons are always pointing out that the cycles of time repeat, "All of this happened before and all of it will happen again." If time repeats, the end is the beginning, and Six must be there.