Sharn.
(It seems I'm boring like that ... the Sharn is my 'hood)
Best,
David
Hey, man, pimpin' the sharn's my job.
That said, yeah, sharn. Advance by two hit dice for more casting and higher ability scores, since you can afford them. You have two LA left to add templates.
You're going to be abusing your spellcasting to the limit, and therefore have sky-high charisma, so sticking on unseelie fey is an excellent idea (bonus: within 5' of you should extend out the hex portals, so "winter's chill" becomes ranged). That's from Dragon Compendiu, is LA+0 and incredibly cheesy (current theory is they gave it a level adjustment by accident), but given that you're getting all this level adjustment for free, I doubt that'll make much of a difference.
Mineral warrior is right out - your fly speed is nice, and you don't want to lose it. Instead, consider two levels of the ghost savage progression (unlimited usage of telekinesis is your friend), shadow creature, or spellwarped.
Phrenic would make you a triple-threat, and, surprise surprise, you can use all three of your ability sets per round. Definiately consider phrenic unseelie fey.
Take mortalbane as a feat - as long as you don't use the same SLA five times the same day, it's +2d6 to all your attacks.
The alternative possibility is being a mistling unseelie fey something. Mistlings are LA+6, and they get the ability to create a living spell from any spell or spell-like they have that fits the template. That's really a cool gimmick, especially if you have a spellthief cohort, and can create unlimited living spells.