Let me explain something to you Thunder:
The strongest Devil Fruit (Nami said it), is the Lightning fruit that Enel posses. With that fruit, he can defeat almost everyone, except for ONE fruit, the RUBEBR fruit. Because Luffy had the Rubber fruit, he was able to defeat Enel, even toh Enel was stronger than Luffy.
Ace has got the Fire fruit, meaning he can melt the Ice of Aokiji's Ice fruit, BUT wihtout the fruits, Aokiji would rape Ace (IMO)
Marsal D. Teach has got the Yami Yami Fruit, and he's the only one that can take away Devil Fruit powers, meaning Logia users like Ace, loses they're special body.
Get it now?
And about your last post here: I'm finished with the anime and the manga, and I don't read the wiki cause you don't get the right info!