So you just got your hands on Diablo 3 – what are you going to do now? There are a lot of great options available to you – you could play through the game, PvP, solo, or farm for items.

However, before you do any of that, you need to decide on the best Diablo 3 builds. It really depends on what type of game you are playing and what you want your character to engage in when acctually playing D3.
For example, suppose you want to play through the game and level up. If this is the case, you will need a nice balanced build that is capable of handling both lots of weak monsters plus boss monsters. This means you will want to focus on maxing out at least one single-target ability for bosses (preferably a short and long ranged attack so you can handle more bosses) as well as maxing out at least one AoE ability to handle large packs of weak monsters.
Now, perhaps you just want to level up. In this case, you might go after as many packs of weak monsters as possible without any concern for bosses. You would just want to max out your AoE abilities in this case and not even pay attention to anything else. Who needs a single target ability when you are simply farming packs of trash? You might want to even pick a spec with buffs so you can level up with a friend.
If you want to farm items, perhaps you might come up with a boss farming spec. This would be something that has great single-target damage so you can take out bosses but also something with good mobility so you can skip past most packs of trash which do not need to be taken out in order to battle the boss. After all, why fight what you don’t have to? If you skip over that stuff, you can just get access to easier and better items and loot.
Finally, you might come up with a PvP build which is ideal for fighting against other players. Diablo 3 builds of this sort would really max out HP and defense. Player attacks tend to do a lot more damage than boss hits, so you need to be prepared to fight other players by maximizing all your defenses so you can last long enough to make the most out of your abilities.