I'm gonna have to say do what will give you the most enjoyment in your day-to-day life.

In regards to the cost, I'll put this in perspective for you: I'm a college student double-majoring in Biology and History. This summer, I'm either working as an EMT-in-training, or as a lab assistant in a neurobiology research lab (if the EMT thing falls through). As you can immagine, these are some of the hardest majors around with some of the greatest time-commitments available to me. What do I do on the weekends? I play WoW with my girlfriend. It is literally the ONLY time I can play WoW, two days a week, and I STILL take the metro to the nearest Best-Buy every two months to keep my account up. It is worth THAT much to me. What am I doing in WoW? I run old dungeons with my guild for achievements and fun, we run BWD for progression, and we generally hang out and help leveling guildies with quests and dungeons. I do all that just two days a week. Just because you don't play often, doesn't mean it's not worth it.

Now, none of my RL friends (besides my GF) play WoW, and I am not fond of any of the people on-campus who play WoW, but the haters here have learned from me. How? When they make fun of me, I just tell them what WoW is, and I'm going to re-use a phrase I used on a breakfast topic a long time ago:

WoW is like a local basketball court. When you go in to play, you can practice dribbling, shoot hoops, and have fun, but it's better when you bring friends with you. When you have friends with you, you can team up, play against and with each other, learn what they are like in the heat of a tense moment.

But in some ways it's better than a local basketball court. When you show up, and people are already there, there's always room for you to play, everyone is always spoiling for a Pick-Up-Game, the rules are set in stone, and best of all, everyone knows who's skins and who's shirts the moment they step onto the court.

THAT is what WoW is, the excitement, intensity, camaraderie, conflict, and rush of victory of a good ball game, all set with a backdrop of a story epic enough to rival the likes of Lord of the Rings, the Icelandic Sagas, or even Star Wars (Strictly the Original Trilogy).

Nowadays, my friends still don't play WoW, but they listen with interest when I tell them of my guild's Glorious wipes and boss-kills, the drama inherent in Heroic PuGs where the shaman healer decided Lava-burst really is worth using his mana on, and the simple satisfaction in finding a rich Pyrite Node while doing Tol'Barad quests.