Power Supply Caps and Xformer

Hello again my ever resourceful allies, :)

So, I'm going to build a big power-supply, but I have 2 questions.
First, the specs of the powersupply:

Needs to be 50V @ 20A = 1000W

Am I correct in assuming that I need a 2000VA transformer for this,
as 2000VA would = 1000W (because of the whole sine wave thing), or
would 1000VA = 1000W?

Finally, what spec capacitor(s) will I need for this?

Thanks!
~Abby