Brace yourself, wall of text incoming.
Holy build really seems to the best for endgame. Right now for season this is a Condemn build using the Blade of Prophecy and the season only legendary shield which removes it's CD. If you playing non-season, then the holy-shotgun build using the Fate of Fell is where its at for endgame. A big reason why I believe the Holy build ends up being best is because of the healing you get from holy cause passive (1% of all holy dmg to life), really helps with survivability in later T-levels.
Lightning and fire is good too. For my non-season sader I used fire (never found a FotF) and I think the ceiling was pretty much T5. For my season I'm using mainly lightning - not sure how far that will take me.
As you may of read/heard, currently in Diablo the gear you find will dictate your build. All the builds want the full Akhans set, so thats no real determining factor. What will probably determine your current build is what weapon and other non-set pieces you find on the road to the full set. Found a Maximus/Cindercoat/Magefist? Go fire. Find a Schaefers axe/thundergod vigor? Go lightning. Found a BoP/FotF? Go Holy (perhaps the blessed shield build can also fit in here if you find that legendary flail and shield combo).
Crusader has a number of builds that can work for farming T1-4 very efficiently. Find one that works best with your current gear until you have the gear for end game builds (BoP or FotF holy builds). As a side note, I find Crusaders work best when pairing with someone (or someones) that have good single target DPS, saders have great AoE but often Rift Guardians can take some time.
I'll see how far the lightning build I have currently can take me. Right now I can do T2 (especially with a good single target companion). I'm not using Akarats Champ yet, will probably use it when I have an RoRG and I'm not keen to farm one just yet (dont have the CDR until then). I also dont have a Reapers wrap yet. With those items it would be interesting to see what T-level I could do with a lightning build.
Link to my season
crusader if you're interested...I still have a long long way to go.
I really want to play.