I remember before getting <img src="/ubbthreads/images/graemlins/div.gif" alt="" /> reading reviews that pointed out that one of its great advantages was how many combinations of skills are adequate to complete the game. Having completed once, and experimented with many characters, I find myself in agreement.
So the first thing I would emphasize--the game is not a quiz on choosing the right skills! Many combinations will work just fine, and since you get skills one at a time, you can always experiment as you go and see what works best for you.
My minimalist suggestion for mages: meteorstrike, hellspikes, something to slow them down (I prefer limbs of lead--doesn't slow them down as much as some spells, but always works), and lockpick. However, you could do without any of the spells and substitute others.
The one thing I strongly advise a mage to do is to learn how to fight and run. This is a game where ranged spells combined with running around a lot can enable even low level mages to beat very high level opponents. You will also find things simpler if you use lots of potions, alchemy is handy for making this cheaper.
