IwubCheeze: I wouldn't say best in the series but it definitely had it's own charm and is certainly no where near as bad as people say. There were some balance issues, that's true, but I honestly believe if HOMM4 wasn't pushed out the door and stayed in development a little longer to work out the issues, it could have been a real contender for best HOMM game.
For campaigns though, HOMM2 was the best. None of the other HOMM games came close.
LiquidOxygen80: I loved HoMMIV for what NWC tried to do. It was just too bad that so many people were still so set on how HoMM3 did things. That being said, IV DID have issues. I hated the storylines and a lot of it just felt rushed. (I'm sure it was, as it was during NWC's twilight years, and I'm sure they thought the game would save their butts.)
The storylines were definately crap although Gaulgoth Halfdead's campaign wasn't bad at all. It was nice for the necromancers to get away from the "we must kill everyone and raise them as undead cannon fodder" cliche. Werjack's campaign was hilarious though. All the talk about community, strength of the community, importance of the community, working together and all that............yet Werjack could solo the rest of the campaign after the first map. Yet, I can't say everyone should have just put their faith in Waerjack because Tarnum's (Waerjack's mentor and main character of the Heroes Chronicles) and his kingdom met their demise because his followers put all their faith in Tarnum and when we was defeated, his kingdom shattered with it.
The worst were the Wind's of War expansion campaigns though. Those campaigns were all "some guy with a goofy / cliched name wants this kingdom for their own.......... cos.........just cos!!" It was hard to take it seriously when the heroes have names like King Spazz (bet he was the butt of many jokes at school), Erutan Revol (Yeah, I totally didn't see you spell "Nature Lover" backwards here), Mongo the Barbarian (Yeah, nice cliched name there).