Race, gender, alignment, romance AC and even body type choice can have signifigant effect on how your story plays out. Just look at the many "which class has the best story?" and see how peoples mileage differs. Some based on preference, others on the choices they made. Some just seem to fit better than others and compliment the stories naturally, and others tend to work out completely akwardly.
First the 4 I've played extensively.
Lightside Miralukan Female Jedi Sage.
The races natural insight into the force just meshes believably with the consular storyline of creating understanding and discovering hidden truths. A woman feels must more natural in the mediator role as well. Frankly Lightside is the only alignment that makes sense to me, the darkside choices make you seem erratic. Sage seems to fit the mysticesque vibe I got from the above choices, shadow seemed off. Romancing nadia does seem really creeperish to me. It seems awesome to me that so many people in this thread seemed to get the exact same feelings I did with this one, they just clicked imo.
Lightside Male Jedi Guardian of any race other than Sith Pureblood, Chiss, Cyborg or Dathomirian Zabrak no bodytype 1 or 4.
This is the blatant hero's journey of the game, not heroines, could you rly see the Emperor's Wrath handing the fate of the galaxy to over to some tiny waif of a woman? Darkside choices kinda make the forced fall to the darkside seem less impactful. Kira seems like the natural romance choice here, but only after your temporary fall to the dark side. This fall combined with knowing just what was at stake combined with Kira's story made this rly my only choice to go against the jedi code the whole story. Sentinel seem too oriented towards aggression and screamed skirting the darkside to me I couldn't reconcile it. The origonal empire pure races like sith, chiss and dathomirian all seem too outlandish to be believable, but any number of races fit otherwise. I have a thing against cyborgs, implants are for people injured in battle or seeking artifical advantage in my mind the hero is a fresh face, who wouldn't pursue power through such artificial means .
Pragmatic Male or Female Chiss, Sniper or Agent. No Humans or Sith Pureblood No bodytype 3 or 4.
Best story in the game, the only real downside to it is the romance options seem sub par compared to others. Chiss feels very natural here, the unwavering dedication to the mission, intelligence and the empire. The professionalism from which the agent approaches his mission and the decisions he/she makes, it seems like such a tribute to thrawn from Heir to the Empire. Pragmatic is the way to go here, I ended up slightly Dark at the end, but in general I made the choice that best benefited the mission and the empire, not myself or the sith. Both ACs have the tools to meld very naturally into the spy role here. With the subpar romances gender seems to matter less in this role as I could see either gender accomplishing the required subterfuge and skill. You need to be an alien in the empire to get the most out of this story! All the romances seem to unbelievable to me, maybe female chiss + vector could work, diplomat on the surface, with an agent dressed as a waitress in the background... just in case
Darkside Male Sith Pureblood, Juggernaut or Marauder. Body type 2 or 3 no 1 or 4 and no Aliens.
Human is the only other race that works here but it feels like sith pureblood was put into the game just for this story. This is a story of birthright, this power has always been yours to take, you are sith, you are the darkside. You crush all those who would oppose you without mercy and use any means necessary to get what you want. Jaesa reinforces the male choice for me here as the other romance options feel abit forced. A completely devoted female apprentice to have little red skinned heirs to my empire? Yes please. What sith tornado of destruction would lower themselves to consorting with Quinn or Pierce? Or awful never shuts up no matter how many times I shock her worthless Vette, bleh. The Emperor's Wrath should be a hulking brute, and a pure blood like all the others the Emperor surrounds himself with.
Next up the one I'm working on my last play through with.
Darkside Male Twilek/Zabrak Bodytype 1 or 3 Assassin. No human or Sith Pureblood.
I'm still on my darkside play through here towards the end of act 2, but so far it feels much more natural than lightside, the argument can be made for starting off lightside but slowly succumbing to the darkside as the story progresses. Using your romance with ashara to manipulate her fall seem very natural which is why i think male works better than female, a rising sith lord and a pirate? Meh. Alien seems a must to me, human could work as well but drawing from one of what the empire considers slave races seems best than the human whos house fell to disgrace ages ago seems better to me. There are no sith pureblood slaves their the nobility of the empire basically I don't even consider that a serious option, any sith pureblood who managed to fall so far would likely be snuffed out as an embarrassment to their kind. As a slave your either gonna be a waif suffering from malnutrition or a brute from years of hard labor, personally i went with waif. Assassin and Sorc both comparatively work well but my personal feeling is that Sin feels better for all the Indiana Jones-esque tomb crawling and ghost hunting.
Onto those I have only had limited playtime with and could use some suggestions. Let me know if you feel I'm on the right or wrong track with these ones guys.
So far I'm leaning towards Male Rattataki, the Rattataki background seems perfect for a BH with Rattatak being a hellhole full of warlords, anarchists and gladitorial arenas. Male is because I want to romance Mako from the moment she started talking, what are the female romance options like here? Anything good I'm missing? As far as alignment I'm thinking pragmatic much like the IA. Hired to kill you? Your getting killed. Just in the way and no chance of you being a problem in the future? Get outta my sight kid. Kinda torn between merc and Ptech here. Bodytype 4 seems to fight the BH lifestyle to me, your not at the gym, your more of a bear sized brawler.
So far I've got a body type 3 Male cyborg who looks alot like Arnold in Terminator 2 lol. I've heard lightside is the way to go here, maybe with a splash of dark when I feel like someone is too great of a threat to the republic to let live, like sith lords and darth's for example. Your a soldier, but one of the republic and it's ideals which means unlike the empire, how you do things is just as meaningful as getting them done. The ends do not justify the means if they compromise the principals of the Republic. Drawing heavily on The Clone Wars troopers here. I've got no clue on romance options here, my alternate is a female body type 4 cyborg. Going the Merc Equiv for both, meleeing with an assault cannon seems dumb to me.
So far I've got a human and a tweilek male, both build around the han solo role. Mostly lightside but not afraid to shoot first if the situation calls for it. I'm out to make money, get the girl and maybe even be the hero if it doesnt seem like its going to get me killed. I got no clue on any romance options here just the feeling that I'm not as bad as my profession makes me look on paper. Bodytype 1 or 2 but I could see a comical bodytype 4 male twilek working here for some reason LoL.