I also read the Animorph series when younger. Used to always get them from the library. Tobias was my favourite POV, then Marco, Ax, Jake, Cassie, then Rachael. I got up to about mid-twenties (and a couple of the early forties, I think) and grew very tired of them...Cassie got right on my nerves and everything was just getting weird. I wikipedia-ed the end, just to see how it did all turn out. I was also surprised to see the extent of the ghostwriting in the series, but in retrospect, I shoudn't have been all that surprised.
I also really like the Artemis Fowl books, particularly the early ones, and definitely The Eternity Code. There's a newer one, isn't there, about...werewolves? The one after The Opal Deception. I haven't read that.
Ah, and I read so very many Goosebumps books when I was younger, and all the random inspired series (like...
...good gods, that's just taken me ages to track down. The Creepers series. Which I think had scarier concepts than the Goosebumps (except for that damned dummy), like the Ghost Writer one were the kid kept dreaming that he was trapped in a room and suffocating. Or the scarecrow in another that crept closer to the house).