I have seen a few of these, on the nexus and on the workshop, but which one is the best? I'm using a magic only character, with no armor, and using all schools of magic. I mainly use destruction and conjuration in combat. I would appreciate some suggestions.

Been asked many many times here - a simple search can get you threads like http://www.gamesas.com/topic/1401294-playing-a-pure-mage-mod-necessities/.

I'd recommend either Empowered Magic or Mighty Magick, but certainly folks will soon post their recommendations like they do every thread.

Workshop though? Pee yew

IMO a rebalance isn't really necessary, what magic is missing are some cool spells. Try Apocalypse and MIdas magic to boost your choices

There is no such thing as "best" in art or entertainment. There are preferences, opinions. My preference is for http://skyrim.nexusmods.com/mods/8451 by AliTheLord. It makes magic perks a bit more effective and interesting and scales spells as the player levels. One of the coolest features of this mod, for me, is that it offers a choice of starting spells. Having a conjured wolf at level 1 was great. This made me feel as though my character was not so much of a blank slate as in vanilla. I felt as though my character already knew a little bit about magic, which makes a lot of roleplaying sense to me.

Personally I like Mighty Magick. Recently updated to v 3.0 and done by a long time modder from the Morrowind and Oblivion days.