Armor Games is the top. The community here is awesome, games are really nice, you can have your personal profile and armatars etc... kongregate is nice too, it just has another focus. I don't like miniclips or addicting games.
i have played many gaming websites, including the ones listed, and armor games flora doras (pwns) all of them! holy balls, armor games is amazing! forums are awsome, and its cool to have ur own profile. plus, armor games is extremely polished and easy to navigate. and of course it has the best games.
I use to play a lot on addictinggames, but it got too commercial, too many ads. But I did play some Armor Games it was hosting there, so it wasn't all bad.
I haven't played on Kongregate or Miniclip (I have played some of their games on other sites, like One More Level), so I can't judge.
Armor Games is my favorite right now, it's the first flash game site I joined.
Might I also recommend One More Level. It was created by the creator of Addicting Games, and it hosts a lot of games from all over. There aren't any comments or community of any sort, though, it's all game focused.
XGen Studios should be on there. They have an membership of ages of 15+, making them slightly better. Plus, they have tons of games. They don't make all of them, but they do host a lot of games. Plus, I like the site layout and friendliness.
Armor of course, all those other sites make me feel isolated, like there is no community, and if there is one it is too stale, like 3 year old crackers