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You can level any class to 60 in 2 hours and equip any class with awesome items in a few minutes.
PvP won't be around for another few weeks at least, and there's absolutely no information whatsoever about what PvP in D3 might entail.
For now, just try out some different classes/builds and play with what you enjoy most, try gaining some paragon levels because it's the only thing that takes time (and I guess 50 paragon levels can make a difference in PvP because of the nice vitality + main stat bonus).