World of Warcraft is excellent IF you want to spend hours on a game and never of run out of things to do. It is a massive timesink, with plenty of things like crafting, fishing and even herbcraft to keep you occupied.
However, it has its downsides. The pvp in that game is terrible, the grinding past level 40 is frustrating and the whole loot raids is daft.
The best game on the market for pvp-based gaming has to be Dark Age of Camelot. Sadly, since Warhammer online is being released by the same company, Dark Age of Camelot lacks up to date features. Yes, they are patches for things like bugs and new monsters, but dont expect to see a vast input of new content, such as zones and things.
But on the plus side, Dark Age of Camelot is around 5 dollers cheaper than World of Warrcraft and especially on the classic American servers(lots of different server types, Classic takes away the pain of one of the most timeconsuming of the normal servers, TOA, and strips the game back to how it used to be years back, when each server had 3k population on it)
There are tons of frree tirals on the website, I recommend you download one of them and go for a drun around. Camelot is also good as it desnt have all the 1337 kiddies, who call you a noob and chaingank you constantly, soemthing that happens all the time in WoW
If you want a huge timesink, go for wow. Fighting more adultminded people in a Camelot type environment, play DAOC