So I've just hit Level 40 and finally got Enchanting to 100 with this character, and I've made myself a set of armour that looks like this -

Helm - Restoration spells cost 25% less to cast. Increases your Magicka by 50 points.
Gauntlets - Two handed attacks do 40% more damage. Increases your Magicka by 50 points.
Boots - Increases your stamina by 50 points. Stamina regenerates 25% faster.
Armour - Increases your stamina by 50 points. Stamina regenerates 25% faster.
Necklace - Increases your stamina by 50 points. Stamina regenerates 25% faster.
Ring - Increases Magic Resistance by 20%. Restoration spells cost 25% less to cast.

I'm an Imperial in Heavy Armour using Two Handed weapons and Restoration, which is why I've gone for so much Stamina really, I quite like the set of enchantments I currently have but struggle with Mages a lot of the time, now with the Lord stone I'll have 45% Magic Resistance, and I'm wondering if the Alteration perks are passive and will work for me all the time, or if they only have an effect whilst casting a spell like Stoneflesh? If not I'll have to re-think my enchantments I suppose.

Any advice or tips on how to combat mages as a bulky two handed warrior would be much appreciated, also. (:

The Alteration perks are permanent buffs. You can get up to 70% Magic Resistance just from passive buffs from Lord's Stone, Agent of Mara quest and the Alteration perks. (Cap is 85%).

Sweet, thanks for that. I'll have to start using Alteration more so I can pick up those perks, as well as look into the Agent of Mara quest. 70% Magic Resistance sure does sound like enough.

I've never needed more, and I play a melee/archer character at lvl 81 on Master. I use a couple of Enchant slots on my gear for Fire Resist.

I find stealth, ranged attack (arrows) and just plain sprinting up to them and hitting them hard all work on mages. Arrows poisoned with Paralyze also work.