I use sword with spell in opposite hand. Block for me makes things too easy, especially Quick Reflexes.
Summons? I much prefer to have someone fighting by my side, so I do go for melee types. If I choose to take Twin Souls, I do like a ranged summon as well. Favorites would be Frost Atronach, Storm Atronach, Seeker, and Wrathman.
Fighting? Ugh. Such crass activity is beneath me. I follow a more refined procedure when dealing with threats, namely:
- conjure two Dremora Lords
- unleash my fierce Lydia
- stand back and watch.
If anything is fortunate enough to get past those three killers, then I simply immobilise it with ice or paralysis until one of them can come over and murder it.