Get in to World of Warcraft if you've never played it!
Pros:
Can run on pretty much any computer.
Large player base
Amazing Story/Lore
Dungeons
Two Factions with a huge rivalry!
Tons of Items and mounts
Amazing and beautiful worlds to explore
Professions
Re playability
Multiple Classes
Classic
Cons:
Can be a quest/dungeon grind
Pay to play
A little outdated
Players can be elitists and unkind to newbies
PvPing is hard when first starting out, due to heirlooms and experienced players
If you find a good realm and guild to join I can guarantee you will love this game. I fell in love the moment I started playing it. I was very overwhelmed when I first started but now it's like I know the game like the back of my hand.