Celestial Monkeys however make GREAT trap detectors! Many a poor celestial monkey has met his end by my Malconvoker
Remember, summoned monsters don't actually die, even though they feel the pain of death before going poof into dust and the re-materializing on their native plane. In the case of celestial monkies, that generally means that you're going to get some holy shit thrown at you when the party starts plane-hopping.
Our DM ruled that it is always the same monkey - and yes - he hates me and is likely stockpiling lots of celetial shit to fling should I ever visit his home plane - though that's unlikely.
(since Summon Elemental Reserve feat I've been using an Earth Elemental though)
Back to prestige classes for GOD in general (capitalizing it like that makes me think it should be some kind of acronym), what about the Escalation Mage in Eberron? Also, are there any other noteworthy GOD classes in Eberron other than Recaster?
I'm afraid I'm not up on my Eberron. FR has some good options though. Certainly Incantatrix is good for any kind of Mage, there's also one in Ancient Empires of Faerun - but I don't remember what it's called (not the Nar Demonbinder!).
Actually, because BC and Buffing is not SL dependant - you can actually do reasonbly well with Hybrids as well. UM is quite good, but I did some playing with the Eldritch Theurge and came up with some builds that looked decent despite the more difficult requirements (depending how your DM rules EB with caster level - this may even be cheatable with Practiced Spellcaster, but not by RAW I believe). I can promise you that despite Warlocks not being the most optimized class - Chilling Tentacles at will is VERY fun. I don't recomend Mystic Theurge to anyone though Arcane Heirophant is a good PRC -but more of a combat-oriented one than a GOD wizard. Wildshape is for Melee characters.
Abjurant Champion is a great PRC not limited to Gishes - don't remember if I mentioned that in the guide. If I didn't - I should have with a
beside it. Free quickened spells are awesome.
The Shadowcraft mage of course is really great - but it makes a good "God" too, largely due to the versatility of Shadow Evocation/Conjuration in terms of BC, not because they get over 100% blasting power. Even a non-heightened spell abuse Shadowcraft Mage should be a good God wizard.
Generally - any PrC that enhances, or at least does not detract from your ability to control the battlefield is a decent option. Look for full spellcaster progression - or a
big payoff for giving up those caster levels.