I really like alternate history stories. They appeal to the history geek buried deep beneath layers of crappy public school education as well as the science fiction geek that's ran the whole Alex show since Star Wars. We could get in a debate as to whether or not alternate history actually is sci-fi, but that's for another time. For a good piece of alternate history that's unmistakable sci-fi, seek out The Guns of the South by Harry Turtledove. It's about a group of South African radicals that travel back in time to give the Confederate army AK-47s. Seriously. It's awesome.
Oh right, Abraham Lincoln: Vampire Hunter. It's alt history in the sense of "hey, let's throw a supernatural thing into the mix of historical events and see what happens!" That should be my bread and butter, but I've never been able to muster enthusiasm, and this trailer doesn't do anything to change that. I have to blame Timur Bekmambetov. I've yet to see something from him that was actually entertaining. Wanted was a mess, and Day and Night Watch were just embarrassing displays of crappy style over no substance.