What neimad is talking about is what I found for EQ2 as well.
Played EQ2 about a couple of months, and got to a decent level (20). I've found, and have heard/read about that from then on EQ2 is fairly group focussed. As in, it will be difficult to level by yourself.
This is a major point of difference with World of Warcraft. There are solo-able quests and content available all the way to level 60. You could play the entire game solo if you so wished. You wouldn't be able to do any of the instances in a meaningful way - you could solo the lower level instances, but there wouldn't be any "good" loot drops or quest rewards that are worthwhile to you at your level, and the higher level instances would kick your butt.
This major point of difference translates to WoW being more "casual gamer" friendly imo. Being that you could jump on and play for an hour or so, and still get the sense that you've "accomplished" something in the game.
EQ2 is very pretty, however, not having had the history of playing the first EQ, I had trouble being drawn into the world. Having played all the Warcraft games, some of the landmarks and NPCs were instantly familiar. This familiarity helped me get some immersion into the game.
Lastly - I love WoW's sense of humour. I'm currently working on "Linken's Sword" quest line. You get it from a small gnome called "Linken" who needs help getting his sword upgraded - he's dressed in green leather, with a pointed hat...
Plus, there's a quest where you find a dwarf locked in an outhouse. He asks you to help him get revenge on the Dark Iron dwarves who locked him in there. Oh, and could you please bring him some silk cloth.. "for ... um.. nothing."
End of the day, I can only recommend trying both games for yourself. What works for me, or someone else, may not work for you.