I am having fun right now playing around with the Djini from the Magic Lamp artifact. I can't quite remember his name.
He comes with 5f/5a/3e/3s for magic paths, which is better than just about anything else you can summon and makes for a lot of nice buffing spells. Plus he's naturally flying, ethereal, and trampling. The Last could be a bad thing for some SCs, but he's also 0 encumbrance.
Sadly, his noncorporeal state means that he lacks feet or body item slots. Anyway, I gave him a ring of regeneration and a bunch of protection and defense boosting items, and he's been quite entertaining to watch.