Setting up HD's on new mac?

Love my new Mac Pro so far, but have not started working with video yet and want to make sure I get my HD's set up correctly first.
I put 3 additional HD's in, that came from a windows machine, so I used disk utility to erase them and set them to FAT, is this all I need to do, or should I actually get new drives that have never been used in win machines.

I have lots of external storage, but wondering about setting up a raid drive for speed. I believe raid 0 splits the data so it can be read faster.

If this is true would I get the same results using a 1tb drive partitioned to (2) 500gb drives or would it need to actually be 2 separate drives?

Denny use the drives as really there are no Windows and Mac hard drives, just different formatting. If the drives are for use in the Mac Pro exclusively may have been better to Partition using GUID under Options, even if you only want one partition, and Mac OS Extended (Jornalled) formatting.