Necromancy, for all your fun-time zombie cuddle-buddy needs! Run off of intelligence but depending on the player you might not be able to tell.

L1:
Flush of life -> non-combat and subtle, lasts a scene. Makes a touched corpse or undead breathe and seem alive. Used for "he's just sleeping", merchants of parrots pining for the fjords, and vamps or zombies that need to pass as alive for a while.
Rot -> combo-ok somatic attack spell. A 1m cube of unattended stuff within 20m degrades. DC 15 rots food, 20 crumbles wood, and 25 corrodes metal into a pile of (probably oxidized) flakes. Are some plastics unaffected? Does it work on Twinkies? Does the floor that guy is standing on count at attended? I'm sure the load bearing beam above him doesn't.
False life -> somatic & verbal 24 hours of temporary hit points. Lets face it, the players won't look twice at the others once the see this one. DC 15 to get one THP, and you get another for every +10 after that. Rolling 10k5 you still get 3 more than 50% of the time and only about an 18% chance of getting 5+.
L2:
Speak with the dead -> non-combat. A corpse answers one question per casting, once a day. While truth is assured, obfuscation is a possibility. That's it, no other limits. Chat up King Tut. And now I want to try casting it on a lich.
Draining touch -> combo-ok touch attack. If the player is a necro casting vamp then they choose this one. Brawling attack for 2k2 damage, if a vamp hits with it they get blood points (resource) equal to wounds done. Under performs on bosses/toughs, works well on mooks.
Burning blood -> combo-on somatic ranged attack. For one round per caster level the struck target, if it has blood, takes one wound at the end if it's turn. Range? Range anyone? LoS horizon sniping? Don't know.
L3:
Torment -> combo-ok, saving throw enabled, attack spell. All creatures within 10m of the caster (yes, including the caster) lose half their remaining hit points (potentially ouch) if they fail an arcana + constitution save. Undead get +5 on the save. Fight opening spell.
Raise dead -> non-combat. Uses a resource point and a 'black gem' (I let fancy onyx Go pieces work, no idea why he only ever bought 30) to turn a corpse into a mook zombie. And they are mooks. See if you can work with your DM to get way to improve them (I did, it's recorded somewhere) or else give them grenades. For funsies I let a DC 100 roll animate mega-fauna. Like, 30m long space squid mega-fauna. He pulled it off once (overcast, gained insanity and blew out the back half of a space shuttle, good thing he was already undead or hard vacuum would have killed him too).
Horrid wilting -> combo-ok attack spell. All foes within 20m lose moisture and take a level of fatigue. Um, save? Nope.
L4:
Corrupted earth -> full round VSM. Oh, it's reverse Consecrate. Except not quite. In a 5m radius around the caster people who worship a different god take -1k0 to all rolls. Half action to sustain, full action to increase the radius by 5m up to 50m. Fades out at the same 5m/minute rate as Consecrate does. Not exactly great for a combat spell.
Consume soul -> combo-ok touch attack that... Ok, seriously? Cast it on a recently dead (one minute or less) creature and they can't be brought back to life as long as you are (un)alive. Really? Really? Just use a thermite grenade like a normal person.
Avasculate -> fill action combo-ok attack. One target within 30m saves arcana + constitution or loses half their current hit points. Nobody gets any bonuses on this one.
L5:
Necromutation -> full action cast with a medallion focus. You hit points go to zero. You can't be healed for the rest of the scene. You are immune to hit point loss for 1d10 rounds +1 round per raise on the casting roll. With the DC 35 that probably won't be too many. Also I think that 'immune to hit point loss' really means 'does not take wounds' because once you're out of hit points wounds cause crits.
Zombie plague -> non-combat & requires a vial of 'dead ' blood. As raise dead but anything the zombies kill rises as another zombie. This is your classic 'masses and masses of zombies' movie spell except that a statline of [def:12 res:4 hp:4 ac:none brawl:3k2, 3k1 R, p=0, percept:4k2, mindless undead] tends to get taken down by random industrial robots or bonobo chimps. For even regular troops these are target practice unless they outnumber more than 20-to-1.

Personal picks:
L1: If you can reliably hit DC 25 then Rot blows holes in the scenery, else false life.
L2: Vamps have draining touch, otherwise it depends on the campaign but I like speak with Yorick.
L3: Zombie master or a hard choice. Although horrid wilting avoids friendly fire.
L4: Avasculate if corrupted earth is being run as written. If Corrupted Earth is run as reverse Consecrate then it's a choice.
L5: Zombie plague, just because I can't bring myself to trust that d10 not to roll 1s all the time. Set the Necromutation duration to necromancy ranks + raises and I'd really consider it because it's minimum 5 and boosters affect it.