I do like games that have long, but good, single player campaigns, however, many MMOs or multi-player games do not need campaigns because the early learning curve is fairly simple and more and more are becoming or are considering free to play, such as the free to play game World of Tanks.
And, World of Tanks is a blast, no pun intended.
Early on the learning curve is very easy, however, it gets steep at higher tiers, and many people are not aware of this because they do not read about tank capabilities, or changes with upgrades, or make friends in the game that can help them out, such as joining a clan. You get medals for many things, such as scouting, but what is the best way to scout, for example? At mid to high tier both an understanding of tactics and the ability to play your tank well are very important.
Besides blowing things up, there are other neat things, like pushing an enemy tank into a lake and drown the crew, or over a cliff and splatter the crew at the bottom. Still, I like to see enemy tanks blow up.
And, unlike other games a new mindset has to be formed. There is no kill stealing in the game, what you earn is based on how much damage you do. Now, if you see a tank at 1% health it is still best to kill it because it takes a gun away from the enemy team.
The game is easy to play on low end or old computers, however, if you have a more powerful computer you can crank up all the eye candy.