Recently built a new pc and been playing the 15 level trial of SWTOR and getting a feel for things. I like the story but ...yeah it's an MMO. Anyway I decided to forego trying to pick a class based on any PvP nonsense and blah blah and I just want to play a class with the most evil story. Backstabing, being a traitor, genocide, murder, lying and being generally unpleasant. Which class will give me that? I usually don't play an evil character in games but I want to break my evil cherry. Also able to solo pretty well would be helpful too as I don't want to group too much. Thanks duders.

Pick a sith warrior and choose all the dark side options. Watch as you suddenly become cartoonishly evil for no real good reason. Bonus points if you keep shocking your twi'lek companion because she dared open her mouth without your consent.

Go Sith Warrior, the Inquisitor is cool but becomes a glorified teasure hunter in act 2 where as the Warrior story plays a lot deeper and more interesting with the politics and betrayal and the dark side.

Edit: I just read the part where you said you are playing the 15 level trial. That pretty much only covers Korriban so you can play either of the sith classes they're pretty much evenly matched in terms of Evil and actually if you just take the Korriban storyline on its own the Inquistor might be more what you are looking for.

Oh dont get me wrong I will probably just buy the full game once the price goes down to 15 dollars sometime this month (that is this month - august - supposedly right)? Sounds like Sith Warrior it is.

If you're only playing the 15 level trial, just give the classes a shot. I believe, from experience, that the Sith classes can be the "evilest." However, be forewarned that, much in this industry's immature style, evil is often misconstrued for being a jack-ass. Most of the things you will do seem so out of place and just jerkish, that you feel dirty being evil. I mean that in the negative way when I am being relative to "evil people."

Early on in the inquisitor story you get to interrogate a prisoner. If you are evil enough you can make him sing you a song.

Just letting you know your options.

Go with Juggernaut. I loved that story. You turn so deliciously evil by the end of it.

...and the part with Jaesa Wilsaam on Hutta...man, SO good.

Isn't there a point in the inqusitor storyline where you torture a prisoner to the point where she is willing to marry you or something?  Or did that get taken out?