I've been specializing in Destruction/Restoration, but some of the perks don't seem useful to me so I've been stockpiling them. For example, I picked up the perks to beef up fire damage by 50% and I just use fire all the time unless I'm fighting a fire resistant enemy. So, I don't think upping my ice or lightning damage is worth the perk points. My stamina rarely drops in combat because I use spells 100% of the time, so the perk to refresh stamina along with health on the restoration path is similarly not worth much to me.

Anyway, finally decided to add Alteration as a 3rd specialization. I'll be going with all non-armor apparel and buffing up the perk that boosts the armor spells.

It would be interesting to play around with enchantment or alchemy, but I would rather use the perks on combat abilities.

Definitely enjoying playing a straight magic user. I have my standard kit down to a never-used dagger, robes, a few potions, and a selection of magical rings/amulets/etc. Once I drop recent loot I head out from Breezehome with barely 20 pounds in my inventory.