New Mac Pro - which monitor, HD and more???

Hi,
I just got a new Mac Pro 6 core 3.5GHz 16GB ram etc.

MONITOR(s)
I am now hunting for a monitor (or should I get 2?)...
What are the options?
Everything I find is HDMI output...is this ok? I though thunderbolt was the way to go.

Hard Drives(s)
It comes with a tiny 256GB hd (I don't get it...why such a machine has such a small hd).
But, for external drives for video, should I get USD3 drives or thunderbolt? What are the pros and cons?

Offer is limited here. So here is what's available:
www.dionwired.co.za/monitors.html
www.istoreonline.co.za/category/83/desktop-hard-drives
www.incredible.co.za/category/1206/storage/
www.dionwired.co.za/portable-storage.html/?p=1

One more thing. Should I upgrade ram to 24 or 32?

Thank you in advance.
joni

I use a single 27" T'bolt display on mine, edit 1080, 2K, 4K, and love it.

But, this is a pure personal choice issue, and what works for others may not work for you.