WARNING: Play the free trial first and don't read half the reviews here, animosity runs high with this game.
Why? WoW is the most successful MMO to date, probably even the highest-grossing video game series ever created. Many may feel threatened by it, many may just plain hate it for reasons known best to themselves. Whatever the case I ignored all the naysaying myself and tried it.
Now, I had been through virtually every other MMO out there; Everquest II, Guild Wars... You name it, I probably tried it. I loved WoW the moment I started it. You may too, just try it. It will not be for everyone. There isn't, wasn't, and never, EVER, will be a game that pleases everyone. But for me, this is the game I may always play, it's a game I always find fun and interesting. It's a relaxing casual experience so yes, Hardcore and Extreme Interest players need not apply.
I implore you to ignore the downraters, and take even the upraters with a grain of salt. Those who hate the game may possibly be honest players who did not like the game, They may be Other MMO fanboys who have never even touched it, or else people who didn't play past level 10, there aren't a whole lot of ways to tell.
Just try the game for yourself and DECIDE for yourself, don't let others guide your interests.