As a full mage I find that I'm fairly untouchable as of yet. I find the versatility of the mage a huge fun factor, and I haven't been able to make my own spells yet. :D

My normal strategy is just to summon a critter to distract the enemy, and pelt em with damage spells. Also, I have Detect Life up most of the time in dungeons to be prepared for what I'm going to face. The general form gives a smart player enough info. Also, Detect Life is fairly cheep, and even a 20 second spell lasts quite a while. Not to mention that your magicka will have replenished by the time it wears off.

Generally, I plan to use invisibility when tough enemies get to close, and have a nice range of spells available to improvise when needed. Things like bound stuff for when I need to be fighterish, summons, invis to flee, regeneration spells, all the stuff that'll make you think before you fight, which is how I like my mages.

Light armor is for when you don't expect to get a high armour skill too soon. Heavy armor will be better in armor rating until you hit master in light(read up on the perks why), but heavy will also impede your spell effectiveness more. Not to mention a normal mage doesn't have too much strength usually, so carrying stuff is going to be hard. (note that a Feather spell in this game is cheap to cast, lasts LONG, and will be replenished before you need to cast it again)

In the end, light armor(glass) will give you the same rating as heavy(daedric), but heavy will last longer. Also note that both armors will not encumber any more at expert(light) and master(heavy) levels.

maybe the encumbrance? it weighs SO much more, it probably destroys your fatigue quickly.

V***V

Light armor weighs a lot less, and a pure mage template has no strength increasing skills. I put blunt instead of alchemy on mine for that purpose.

...Makes a person miss the "Unarmored" proficiency... :(