So, what class do you like to play in Arena?
I happen to like Sorcerer (lots of SP, innate spell absorption, and the interesting limitation of not regaining SP through resting (but Potions of Restore Power exist), Nightblade (magic + thief skills, also gets a discount on some spell effects (notably including Open, allowing me to open locked doors that would normally require a large detour to get a key for, like the ones in the Labyrinthian), and when I want something other than a caster, I go with Knight (can automatically repair weapons and armor, including those that cast spells when used as an item).
I only ever played Spellsword and Knight. Knight is definitely harder to play of those two. Spellsword is probably one of the easiest classes to play, but I just like roleplaying the idea of being both warrior and a mage, a warrior scholar. I play Spellsword or Spellsword-like classes/playstyles in all TES games actually (I always make my own class in Daggerfall which is kinda-like-Spellsword).
That being said, maybe I'll try something different this time. Monk seems like an interesting class, though most likely hard as hell to play.
Interestingly enough, Sorcerer can use all the weapons and armor (but not shields) that a Spellsword can can use.
The playing style is rather interesting: When you are fighting enemies that don't use magic, you play like a warrior, albeit one with fewer hit points but some emergency magic use. When you are fighting enemies that do use magic, you switch to playing as a mage, so you can use all that extra SP you get. It can be quite fun.
(Worth noting that Potions of Restore Power will restore SP, and using them can make playing as a Sorcerer significantly easier. If you want, you can attempt Sorcerer without using these potions.)
For Knight, my favorite approach is to get some weapons that cast offensive spells (particularly Lifesteal and Firestorm) and use their spells as my primary form of offense. Since I'm a Knight, in this instance, I don't need to worry about manually repairing these weapons.
Then again, it turns out that, if you drop off an item for repair and ask for it to be ready in 2048 days (or any multiple thereof), it will be ready instantly. Gotta love those integer overflow bugs.