Re: Making a super villain team.
I rarely stick together the pre-published ones, instead going for char's who can be 'tailored' to the characters they oppose. I'm particularly fond of making nemeses who work out for particular char's specifically.
Taking a look at a few examples - Steele would be good to oppose with either a handsome rogue type, or a stalkery jerk. So, from published, I'd pick out Stormfront (CKC), or come up with somebody from her past if I was going original (say, a psychotic mob boss' granddaughter, newly given powers by a mystic she's bargained with.) I don't always match character types - doesn't have to be brick v brick - but I don't go for polar opposites either. Brick v mentalist is a very, very bad pairing for hero and nemesis, unless there's something there. Similar types work well, as it creates a sense of rivalry as well as antagonism. Not necessarily similar powers, but similar personality.
For a whole group, you need to work on making sure they've got a reason to work together. The Fiendish Five approach works well - "we *all* hate them, so let's work together!" But you're better off letting the villains work together on their own too. They might join to oppose the heroes, but they stick together because it goes swimmingly after that - the most dangerous sort of team, since you can't play off of "X is going to double cross Y, you know."