The most fun I had as a mage, by far, was as a battlemage.
I was an Imperial, but mostly because "Imperial Battlemage" had a nice ring to it. Being rich and having no need to invest in Illusion was a bonus, though.
Skills were, at first, Conjuration (just Novice Conjuration and the weapon perks except Oblivion Binding, so pretty lax in that tree, though it got very high from usage), Alteration (almost everything), Restoration (about half the perks) and One Handed (Armsman and the power attack perks--no weapon specialization or dual wielding).
Bound Sword in my right hand, magic armor in my left and a hotkeyed heal spell to go along with it. Battles were quick, easy and fun. Soon, I found myself with more souls and perks than I knew what to do with, so I invested in Enchanting and Smithing. Made myself some nice new toys. Voice of the Emperor came very much in handy and was useful throughout the game, since it works in an amazingly large AOE and affects humanoids regardless of level; it saved my rump more than a few times.
Around my 30's, I realized I was approaching every problem the same way: sword and armor thrown out with healing at the ready, dishing out pain as necessary and mass-calming when I needed to, but it occured to me that I could do a lot more with the two magic schools I had already invested a lot in (and necessarily so). So I began to do things like paralyze my opponents and ward off magics, but I guess that wasn't as exciting as jumping into the mayhem.
Shouts made the build all the more special. I'm thinking of making him all over again (deleted him to save memory space, but I had him long enough to be satisfied), but I'm thinking of investing in Destruction next time instead of Smithing. Keeps my magic more focused than combat skills as well as varied (I think Smithing is when I started to have less fun with it). I figure Enchanting will bring me enough damage, and the variety that Destruction provides can be defensive: I'll use runes, walls and cloaks, making my melee mage that much more potent. I'm falling in love already
