Well, I don't really like any of them to be honest...all of them turn out to be good guys (except Orochimaru but I hate that creep). Gaara became a good guy, so did Zabuza in the end.
If you read the manga, then you'd know that Itachi was never a bad guy and Pain turns good as well because of Naruto...so all I can hope for is that Madara is pure evil with no good in him. I personally like him for being the mastermind behind the Akatsuki and for having the EMS.