Switching to OS X : How to be prepared for smooth transition ?

If u remember me , I made like 7-8 posts from Sept regarding OS X and Finally getting Mini.

I am going to finally get Mac Mini , 2.3Ghz Quad core version w/ 4 GB RAM , 1 TB HDD probably by end of this month or in two weeks time.

These are too many questions in my head whenever i think about OS X :

So , My iTunes library can be shifted easy or i should re build it ? Whats the best way to shift it with minimal data loss ?

Can i use my Appstore ID on Mac App store ?

Should i need anti virus ?

Which connection gives best 'display' output apart from thunderbolt for a Mini ?

How well do windows keyboards and mice work for a mac ?

Is it possible to send files over bluetooth to non-Apple devices from Mac ?

How much RAM is good for smooth experience even during little heavy usage ?

And is there something I need to keep in mind ?