I wander around with a short sword and Atronach in my left hand. If stuff emerges I cast the Atronach and if they are not too tough I bash em' with the sword.
I have nothing in one handed but it works well for that. If stuff gets serious I pull out the big sword, bound to "1" on my PC where I have all my perks and beat on the boss or whatever is causing my Atronach trouble. I have the Battlemage at level 40 now and with all Deadric I am at the armor cap and the big sword hits at 120. I one shot bosses sometimes with decapitations every once in a while. The big sword does almost 500 damage with a critcal power attack.
Done with the Battle part I'm getting his Conjure and Illusion up some. He does destruction with the big sword and as he is in battle when he needs health I just pop potions for health. For Alteration all I need is the candle really.

Some Alchemy and some Enchanting skills as well but nothing too over powered.
He's my third after a Mage and sneaky Kajiit. Toughest build as he has a wide range of attributes.