Magic Online. If you enjoy Magic The Gathering, you will tolerate Magic Online. If any game with Magic's mechanics was put online, it would do quite poorly. Only because of Magic's 18-year history can a game with so many bugs and so many "OK/Cancel" dialog boxes be so sucessful. And yet, I have spent over $1000 playing this game. I have yet to see a head-to-head strategy game better than Magic Online. I'm "bsr Orion Purple" if you want a match.
League of Legends, a free-to-play Massive Online Battle Arena game. Some people want to call it an Action RPG, but there is no roleplaying. What there is, is a fantastic team-based third-person action game where you and four friends play as Summoners, advancing from your Nexus, through opposing defenses and Summoners, in an attempt to destroy their nexus. League of Legends is the Magic the Gathering of competitive multiplayer online gaming.
You Don't Know JACK is the very best trivia game you can play by yourself. Because it really isn't about the trivia. It really is about the LOL. And for 15 years, Jellyvision has been bringing the LOL.
What I'm Playing Offline
Rock Band 3.
This game lets you be a rock star. What else is there to say? How about "Buy this now?" I have been a fan of Harmonix forever -- goting all the way back to their first games Frequency and Amplitude. Yes, you can play this game online. But the real fun is playing it with three friends in your living room.
Magic: the Gathering.
This game is the reason I started making strategy games professionally. It is brilliant on so many levels. It seems likely that I will be playing this game 15 years from now.
World of Warcraft. I'm playing this partly out of fun and mostly out of requirement. WOW is a requirement for industry understanding, and until I have a level 60, 70, 80, 85 character there have more to learn.
Astral Tournament. Decent little game. Plays like a CCG but is more of a strategy game that happens to use cards. You do not build a deck, but instead have access to all of your cards every turn (but you may not have the resources to play everything). My account name is Audera Blue.
City of Heroes. A MMORPG where you play a super hero trying to defend Paragon City. Even without being on a "roleplaying" server, people still spend the time making interesting little character histories. I enjoy that to no end. Unfortunately, it is about to be taken offline. So get your game on while you can...
Rift. This MMO is a great evolution of the World of Warcraft style of game, with much more flexibility in character skill development and more and varied types of quests and adventures. I stopped at level 40 (out of 50) to log more hours of WoW but I will get back to Rift soon.
Dungeons & Dragons.
The 4th edition rules make this game great. Just don't call it a roleplaying game, OK? It is a tactical strategy wargame with fantasy
trappings. It is fun! I enjoy it a great deal! But if I wanted to actually roleplay, I'd play something else.