Look around. Many times, especially with World of Warcraft, they offer free play times. You can download it from Filefront on occasion, and they allow you to play for between 10-30 days, depending on the offer they have going at the time.
I would suggest looking out for one of these offers before spending your money and buying it. Or ask some of your friends who might have a copy. Many times, Blizzard extends invitations to these people so they can get their friends to try it out. I have been asked many times whether I wanted to try the game, but personally, my answer has always been a resounding "NO".
My reasons for not wanting to play WOW might differ from others, but what it all comes down to is this - I have a hard enough time living my life in the real world (managing money, time, family), that I can't imagine spending what little free time I DO have bettering the life of an online character.
I have friends who have almost lost their families due to the completely engrossing gameplay of WOW. I never want to be "That guy" that this happens to. There's a reason why this game is sometimes referred to as WarCRACK. It's just as addictive as crack, and people play the game to the exclusion of everything around them - families, jobs etc.
For a good satirical take on the whole game, and MMORPG's, check out the South Park episode "Make Love, Not Warcraft". I swear to God, that this is probably the MOST ACCURATE depiction of MMORPG players I have ever seen - This is what all of my friends who have played WOW eventually degenerate into.
Regardless, try it before you buy it. There are always offers being run for the game, and here's the link for a free 10-day trial from the Blizzard site.
https://signup.worldofwarcraft.com/trial/index.htm
If you like it, by all means, go out and buy it - just don't say you weren't warned about the addictive quality of the game. I'm proud that I haven't been hooked on anything like this yet, and hope never to be hooked on it. But if you can separate your online life, and real life, you're probably ahead of 50% of the people playing WOW.
I think World of Warcraft's tagline says it all.
If you think that it's not a game then you are dead wrong....