I have access to any Druid, Cleric, Wizard, and Sorcerer spell. So, short answer, both.
Wizard style casting, but the spells I can cast each turn (from my prepared spells) are randomised to a certain extent.
Party role... nothing defined, really. My current spell selection is a bunch of rays. I was thinking, to go totally off the beaten track to only prepare summon spells (which would give me a few feats I could then use effectively). But it's sort of all up in the air.
Doesn't Invisibility Spell have a prereq of a metamagic feat? As that is definitely one I'm interested in taking. I was just stuck on getting hold of a no prereq metmagic feat that didn't change spell slot levels.
Spell Focus, Greater Spell Focus, and Improved Initiative.
These were on my list too. I added Spell Penetration as well as I was pretty much stuck on what I could choose.
What about things like Craft: Wondorous Item or Craft: Rod/Wand?
Flavour wise my character worships the goddess of luck. So maybe there are Luck based feats to fill it out a bit. I don't have access to the Luck domain, but I might be able to swing it if it opens up extra feats. I just won't be able to cast the spells from the domain spell list :S
EDIT: Thank you both for the replies, btw.