Birthsign choice

Atronach: Entirely different style of gameplay. After you get the items to make yourself 100% absorbent you will no longer be dodging spells but jumping into them. This sign makes for a decent counter-mage.

Apprentice: Trade resistance for magicka. Don't bother unless you can dodge most spells and arrows. Even then, a sword of sparks goes from being useless but expensive phat lewts to being a potentially dangerous adversary. I'd recommend Breton for all mages, but Apprentice mages in particular.

Lady: Arguably the two most important abilities at level 1. I have argued in favour of that before. You won't be shrouded in protective magics right from the start, so it does help to be not quite as squishy as you could be. This birthsign is good for any race/class combo, which is the only reason you shouldn't choose it: pick something more mage-y. I've played a Ladymage though, and +10 Wis really does help.

Lord: Meh. Maybe its good for meatshields, in particular if they use it in combination with a transcendent sigil stoned hood of magicka +50 (allowing them to cast the spell repeatedly). Pointless for mages, you will make much better pots and eventually your restoration spells will overtake it.

Mage: This is suckier version of Apprentice. If you wanted to tank damage, you picked the wrong class. Take one of the more offensive-focussed magicka boosters.

Lover: lololol. 1 use of paralyze, but not viably in combat (fatigue loss = KO = dead). also, the serpent doomstone gives a shorter but more combat-effective one. if you really need paralyze early on, then use the doomstones one.

Ritual: lol no. It's basically carrying around 1 extra pot of strong heal. What are you saving? 0.5lbs? That and a free turn-undead spell. Don't get me wrong... Turn Undead is good, but you can buy it off one of those mages with shit mercantile for chicken poo.

Serpent: Oh wow this sucks. Real slow DoT, dispel your buffs/summons? AND you sac 100 fatigue?

Shadow: This sucks more. Why? Early access to invis - handy yes. good no. since you never want to improve your personality attribute, you should feel free to pump your illusion up to 100 before you even get to level 2. you first get invis at illusion 50 (ideally deathly visage from m'raaj-dar) so you dont have to wait long anyway. this is also why illusion should NEVER be in your major skills, because its perhaps the only skill you can freely and easily pump.

Steed: Good for thief/assassin/archer types. It's not for mages - it doesn't augment casting.

Thief: +10 Luck? Sweet! The other two are added extras - the steak knives that come with the silver kitchenware. If you are going to take this sign, then couple it with a class' favourite attribute being luck. starting with 65 luck will make the early game quite a bit easier.

Tower: Terrible. Just terrible. If you hate the lockpicking minigame that much, at level 10 you can do Nocturnal's quest.

Warrior: +10 Endurance is nothing to be laughed at. Oh except, the Lady does the same thing, but she also give Wisdom which is even more important. Needless to say, this ones not for you.


In conclusion...

Lady, Apprentice or Thief are all good choices. Don't be fooled into thinking Atronach is powerful - it's significantly less powerful but it does allow a different style of play which is at the very least intriguing. I'd say go Lady for the more conservative, balanced mage. And pick Apprentice if you want offence at the cost of defence. And Thief if you want to max out your starting luck (you wont get to 100 - well-made mages get boring after about level 25 once nothing can kill them and they can kill anything and that would give you 89 luck)