I was a huge fan of Streets of Rage 2. I only missed the option to call the friendly police attack from Streets of Rage one.
Is it my personal best Beat them up? No;..
During the Sega Saturn generation you had something called Guardian heroes;....And that is really more fun + And recently Castle Crashers became my most favourite beat them up.
And I think some also forgot the awesomeness of TMNT IV Turtles in Time =p.
By the way if you are interested Top ten beat them up from Screwattack.