Yeah, World of Warcraft is a lot of fun! It is really easy to get addicted though, especially if you have friends that also play and you want to catch up to them or stay around their level. It is pretty cheap to play, $15 a month, but you can make as many characters as you want on whatever servers you want too.
If you do want to play, I would buy the original game, and only get The Burning Crusade if you really want to make a Blood Elf or Draenei character (those two races are only available through Burning Crusade). The newest expansion pack, Wrath of the Lich King, is coming out on November 13, which adds a lot more content and raises the max level to 80.
The Battle Chest Bundle is a pretty good deal. You don't actually need the strategy guides, as you can find all the information you need online, but they would be nice to have so you don't have to minimize the game to look stuff up all the time.
If you have a lot of free time to play, and don't mind paying $15 a month, I really suggest it! Its a lot of fun, me and a bunch of my friends all play together, which makes it even more fun.
If you do decide to play, send me an email and we can do the Recruit-a-Friend option. That way, we both get experience bonuses when playing to level up quicker and get a free mount!