What are the best destruction spells?

Is fire or Lightning better?

Should I bother sinking points into magicka if you can get 100% reduction? If not, how does that work?

fire is more dmg but lightning is faster and has less ressistances either one is good I think lightning is better due to it being better at longer ranges and you won't miss as much making up for damage

as for the enchantment it really depends how fast your going to learn enchanting if you do it ASAP you won't need magicka halfway into the game however you will

Master them all. There are bunch of creatures and whatnots that can resist one of the type completley.

Fire does extra damage
Frost depletes targets stamina aswell
Shock depletes targets mana aswell

If your main offensive skill is going to be destruction magic then you better master the whole tree.

Thanks guys.

Does wearing armor have any effect on magic?

I personally would go with lightning because practically nothing resists it. But if you have the perks go with both fire n lightning.

unlike oblivion no I suggest you do due to there being almost no unenchanted robes and the archmages robes look like a poncho

So there is no penalty to magic for wearing armor at all? Is it just as good to wear armor too?

It doesn't effect magic it all. It's really up to you whether you wear it or not.