ekental, here are some suggestions about chromatic orb and a few others...both you and nephtu have made some excellent and valid points..
chromatic orb is best used in spell sequencer, following a malison, then two chromatic orbs...whats great about the spell is you can also prepare a minor sequencer of 2 chromatic orbs to to a second spell attack next round...i agree chromatic orb is a wonderful spell, it really can be a low cost finger of death if you hit a target with enough of them...have all your mages with chromatic orbs in all the sequencer spells you have do a mass launch against a dragon...funnier than heck...
melf is a great spell for disrupting mages, and killing trolls, however as nephtu pointed out, it doesn't scale up...which is why many people think that waiting for melf minute meteors is the way to go...useful against demi liches, some fun tricks, like equipping an off handed weapon, and using with improved haste is the way to go. i actually get them both, since melf acid arrows becomes very useful used in a minor sequencer.
here is a fun trick with dispell magic...lots of people don't like dispell, since it WILL blast away your combat protections, (Your spells will always affect you...) and think that remove magic is the way to go...i usually have both...however, if you don't have an inquisitor, try in preparing for combat casting spell immunity abjuration after casting your buffing spells, like stoneskin and mirror image on yourself. you can now cast dispell magic like crazy and it wont remove your spell protections!!! using this trick, i would rate dispell at least as useful as remove magic...
i rather like chain lightning, but 6 level spell selection is always hard, lots of great spells there, and if i have a specific spell in mind i sometimes dump it. however, it is the last direct damage spell you can spell trigger, so i usually keep it. spell trigger makes it much more useful, especially against mutiple targets...
i completely agree with nephtu about cloudkill...wands make the spell useless...same goes for fireball...stick to skull traps, which have a much higher cap...it is fun tho...but so is having a party of all mages point fireball wands at a group of orcs, and all unleashing a fireball in the same round...firing squad style...
urm...breach is all you really ever need...spell protections only block TARGETTED spells...
unless you have tactics mod installed, you only need breach and remove/dispell magic for the entire game...
spell protections like spell turning or spell trap will not stop abi dahzim strikes, or fireballs or skull traps...
its also tactically sound to use opposing tactics against enemies...for example, you should use magic on monsters who can't use magic, and whack mages and spell casters...breach and whack away.
remove and dispell magic is for fighting liches...who despite the description saying they're immune to 5th level spells and below, you can remove magic or dispell their physical protections...use spell sequencer to do a good job...
now, only if you get tactics mod smarter mages component installed do you need spell protection removal spells...and ruby ray is the best selection for that task...
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They call me Darth...
Darth Gizka!
Muwahahahahhahahha!!!