The kind of character I want to have with an Ally Spirit is my Black Magician (and I use the 4th edition description of the tradition, where it's less cartoonishly evil than 5th) who would have an ally spirit with Possession. They'd be kind of like a mentor spirit in that it'd be a constant presence in the back of your mind. While possession is now the weakest of the three, a +3 to all my physical attributes would still be pretty nice, and the other abilities it offers are good enough. Plus, using stuff like Energy Aura or Elemental Attack is still real useful.
If I was gonna do Inhabitation, while what TerraFirst! says it cool (though not something most could expect to do, and you gotta remember, it's all on how the inhabitation roll goes), I'd wanna pick some kind of small, harmless animal. The idea of having a bullet-proof cat fully capable of murdering someone in a single swipe is great. Not to mention they'd be quite good at stealth by virtue of being small and a cat.
Is your character's name Belkar?
