I run Fraps (free edition) to get this functionality. Also if you run EntropiaLife client that automatically screen shots globals, hofs etc.
I have fraps. Another question. Yesterday I had an HP increas. Where do I see my total HP in numbers?
If you go to your Skills folder (K) and click on: Attributes, you can see your avatar's Health listed as the second attribute after Agility.
Hitpoints = health. You can see your max expressed as a number if you follow Archangels advice. Don't think there is any place to see ur current hp as a number.