My take on this subject. In no particular order.
Spectacle: The Kop when Liverpool come out onto the pitch. Scarfs, banners, flags, you'll never walk alone, etc. The Poznan at COMS.(and away from home) When it's done en-masse, it looks awesome. Nothing at any other club springs to mind.
Best home support: Stoke, Newcastle United, Spurs.(to an extent) Not the variety of songs, as neither club has that many, but the sheer noise that is generated around the whole stadium and for long periods.
Songs: United, City, Liverpool. United have had the monopoly on new songs over the years, thanks to a certain fat b****** Boyle. However, since the Blue Alliance was formed and the Poznan kicked in, we''ve come up with numerous new songs this season. Liverpool have done pretty well of late as well.
Best banter: This is a hard one, as it's different at every gorund. But I firmly believe City are the best. Time after time this season away fans have been at the sharp end of our banter and wit at COMS.(and complimented us on their forums) When City travel you never get the same thing from the home fans. Behind City are Villa. They sufferd twice at COMS this season and they took the stick, but came back with banter of their own.
Best away Support. United. It's easy to sing when your team is always winning, but they are well organized away from home vocally, and always get behind their team.(too many City songs though) Liverpool, Newcastle and City aren't that far behind. Always giving good away support.
Overrated support at home: Liverpool and Sunderland. Liverpool are great when they're winning, but if they're losing or drawing, you can hear a pin drop at Anfield. TBH I don't know why people rate Sunderland's home support. Apart from the Roker Roar, as it was called, there isn't that much singning going on.
Worst home support: Arsenal, Everton and Birmingham. Arsenal is still the library, but it's moved to the Emirtates. Everton is noisy(constant moaning), but the odd chant of "Everton, Everton, Everton, is pretty dire TBH. Birmingham. One song every now and again.
As far as I'm concerned there isn't one set of fans that can claim to be the best. Theyal have their pluses and minuses