If I were to do it all over again, I'd look for these pieces:
Of The Falcon (Agi + Int)
Of Power (AP)
Of the Monkey (Agi + Stam)
Of Agility (twice as much Agi as mixed stat gear)
Of The Wolf (Agi + Spirit)
In that order. But like Cal said, it's really complicated, because you DO have to think about your attack power and DPS, but you also have to think about how everything will effect your pet, as well. Of course, of the Falcon will affect your DPS a litle bit, and contribute to your Mana, while still giving your pet a nice boost in armor. Of Power will do a lot for your DPS, but next to nothing for your pet. Monkey will affect your DPS the same amount as Falcon, except without the mana boost, but it will REALLY benefit your pet. Agility will give you extra crit and dodge while giving you a small boost in AP, but that armor that you get from it, goes straight to Fluffy.
I say get a nice mix, and stay away from str.. Until you're level 60+, it doesn't matter very much, since you're going to swap out gear every few levels... Unless you're like me, and stayed with level 40 gear up until about 53, because I *couldn't* find anything better. I swear that there was a level gap in green gear.