When is day-time for the purpose of vampirism(‘s Weakness to Sunlight)

You're right, the Damage Magicka and Damage Stamina enchantments aren't terribly efficient.

Absorb Magicka and Stamina have their place, but in general, you'll find opponents regen Magicka to fast for Magicka damage to be terribly useful - generally, by the time you've done enough for it to be really effective, you've hit them enough times to kill them anyway. Stamina is a bit more useful - an opponent with low Stamina will have trouble blocking and power attacking, which can shorten a protracted battle, but given the magnitude and base uses of the enchant, you're often much better off using an Frost Damage or Absorb Stamina enchant - you'll find them to be much more effective overall.

Edit: various rebalances in patches since the below was posted (such as a particular spell's damage per cast) has made it inaccurate. I am afraid, therefore, that it seems that the author of the spreadsheet has taken down the link.

A Solution

I developed a basic spreadsheet that allows you to find out all the above questions, and more. V1 provides a full workup of magicka and all related enchanting effects, and provides detailed damage info for destruction spells.

A better VBA model I was 30% through is on hold while I enjoy a DLC to my favourite game :D

An basic example with my current mage: Magistra Circe

Mirror 1: SkyrimNexus

EDIT: the sheet is locked to prevent accidental deletion of a formula. You can unlock it (no password) under the "Review" Tab (in Excel).