Divination, uses wisdom. Personally I like this school.

L1:
Augury -> DC 20 non-combat cast to get a general idea if your current course of action will have a positive or negative outcome. Failure gets a false reading. No other real limits or guidance written down.
Whisper -> combo-Ok subtle line of sight single target short message. Unimpressive.
Detect thoughts -> subtle non-combat mind affecting that gets you the target's general emotional state. Roll equal or higher than the target's mental defense and get actual thoughts. Beat that by raises equal to the target's willpower and do a deep probe for the answer to a single question.
L2:
Foresee -> somatic reaction to dodge. Basically swap acrobatics + dexterity with divination + wisdom & possible warp rolls.
Luck -> combo-Ok subtle spell to get an extra luck die to use on tests. DC 20 and every 5 gets you another die. You can't spend more dice on a roll than your level. Unspent dice poof at the end of the scene.
Arcane eye -> material component is an eyeball, cast out of combat to get a tiny "difficult to spot" magical sensor that moves at your base speed and has a range of 4 kilometres. Senses are normal for your race (not your exalt?) and magical or technological boosts don't work through it. Any damage pops it.
L3:
Scry -> a focus requiring non-combat spell that lasts as long as you spend a half action to maintain it. You need an object or body part from the target (sell them something if they use cash) and they get an arcana + willpower save to negate the spell. It gives you a 10m radius vision around the target. You can probably get some pretty hoopy effects if you use a 10m radius fun-house mirror as the focus and cast it on yourself while standing in the middle.
Precognition -> combo-Ok and subtle. Works like Luck but the DC is 5 higher and it gives you re-rolls instead. You can spend as many of them on a test as you like.
Legend lore -> non-combat History channel documentary spell for stuff. Should probably work on people without having to kill them first too, although that might change police interrogations a bit.
L4:
Mind net -> subtle mind affecting telepathic network with your allies. I'd limit it to people reasonably nearby and let you include other people you see and know in addition to 'allies'. May or may not work on Chosen of Malal even if they're on your side, but that's just my interpretation.
Unluck -> attack divination! Subtle, save, combo-Ok. DC 30 to make a target within 10m lose a die from ALL ROLLS for the rest of the scene if they can't beat you with an arcana + willpower save. Every raise on the casting test strips another die from them. If you can hit 50 you can turn someone's 5k5 damage man-portable laz cannon into a flash-light.
Foresee -> non-combat augury on steroids. The DM has to give you a vague but useful idea of the next (DM's best guess) threat to you and something of what you can do to prepare for it. When the threat comes up or is prevented/skipped the spell pings again to tell you that time of the threat is now. The DM doesn't have to be specific but does have to be useful, and it acknowledges that DMs aren't perfect at predicting player actions.
L5:
Commune -> a six keyword spell, one of which is social so no combat casting this one. It lets you talk to anyone you can name for five minutes. So what happens if I name "Mr. Smith"? Oh, wait... Loth, Pelor, Nurgle, Khorn. Heyyyy, I can prank call gods! There's no way that could go wrong.
Hindsight -> non-combat concentration (reaction) spell that lets you see the past. Historical events or named dates and times. You can walk around and look but no interaction because its just a vision or illusion.

Personal ratings
L1: Augury or detect thoughts. That will depend on how combat oriented the campaign is.
L2: Luck, but I want foresee too. Hard choices.
L3: Almost certainly precognition. Depending on the game maybe scry, maybe.
L4: Unluck if I have luck & precognition. Foresee if there are lots and lots of unpleasant ambushes with no warning or the game is a train job but the DM is fair.
L5: Prank calling gods.

I think that divination is really my favourite of all the magic schools.