I haven't played Lineage2, but I have and still do play WoW. I've played alot of MMO's and by far WoW has been my favorite. I know Lineage2 is huge over in Asia, I think it has the most worldwide subscribers so I'm guessing that its probably a pretty good game as well.
For me though I like the fact that I don't necessarily need a group to do everything in this game, I can solo to 60 if I have to, whereas in something like EQ, and EQ2 you need a group fairly early on to do anything in the game.
If you do get WoW let me know, if you get on the same server as me I'll hook you up with some gold and stuff.