Different paths

I'm on my first playthrough, just entered Act 2, I think. I'm playing a pretty typical 'good guy' run, and already thinking ahead to future runs, but I'm not sure what kinds of runs are actually possible. What factions can we decide to side with? Can you be pro-Gith? Pro-Absolute? Is there a possibly playthrough for "evil but acting like you're good to string along the actually good people so you can betray them at the end for huge pay-off"? Are there even more varied options that I've not realized yet? I'd like to hear ideas and/or run styles you folks have done.