I dunno. I mean, a while ago, I would have said Onua, easily, but now that I sit back and think on it in an unbiased manner... I do like Onua still, it's true, but I'm not sure he's my overall favourite anymore; I think I was biased previously because he was my first set ever. Recently, I've stated to like Gali a lot, possibly the most. I feel she's sadly underrated, to be honest; always doing her best to keep the other Toa together, never with much true success. Though Kopaka is pretty cool (no pun intended) too; and I've always had a soft spot for Pohatu as he appeared in the early comics and Tales of the Masks - though I didn't like him so much in the post-Metru-Nui novels, he just never quite seemed the same to me in them. Maybe that's just the nostalgia speaking, though. As for choosing a favourite; after some thought I'd say it's actually about equal between Gali and Kopaka, really - though my vote goes to Gali because she seems the more unappreciated of the two. Then, for the sake of having a full order, Pohatu and Onua share joint third place, I think; then Lewa, with Tahu being my personal least favourite.