To counter Ds points on WoW vs GW: On my druid, when I hit level 60, I had put in about 20 days of play time. Thats ~480 hours to reach the highest level with very little "grinding"...I mostly quested and did a lot of exploring, crafting, fishing, etc.
Thats just one character, too. I have a horde druid at level 54 or so, a 42 rogue, a 30 mage, and a 20 shaman. Not including the other classes I leveled to 10 just check em out (warlock, priest, warrior). Now the expansion with its new area and 60-70 quests are said to take nearly as long to complete.
There are some fundamental differences to be aware of. GW isnt really massively multiplayer in the same way as WoW. In GW, you go to town and its full of people. Once you leave town you are on your own or with your party. You wont see other people running around killing things.
This has pros and cons. On the pro side, if you're in an area attempting a difficult quest and you notice someone else doing the same thing you can ask to team up and get it accomplished together. Or sometimes a groups just cleared an area you were headed through which can save you time clearing it yourself. On the con side, sometimes you'll be fighting hard, clearing an area to get a specific item and someone will jump in and take it from you (like if you're clearing the way for you to mine some mithril or something and some jerk mines it while you're fighting right next to it).
I've had both those things happen to me in WoW. It adds some interest...the human element.
Cost isnt so bad. WoW is $16 this week at best buy(I believe) with a free month of play. Thats like giving the game away for free and you only pay the server fees.
Pug if you want I can give you a WoW free trial code for you to play the game. Its like 10 or 14 days, you download the client for free. That way if you sign up later they give me a free month...hehe.