Vhite said:
If you want a long lasting game with descent end game content, city of heroes is a good start.
Its a pretty old game, the combat isn't anything special, and the older/majority missions can feel samey, but overall it's a fun game. and a lot better when you play with other people.
It's got a good number of archetypes(classes) and you unlock extra when you reach level 20 which adds to the time you can spend playing.
It has an incarnates system, which is super strength end game content stuff which is designed to take you over 2 weeks of play per stage.
The difficulty settings mean you could bash out 10+ missions in half an hour, or spend an entire session on a mission set to the highest difficulty. (one of the best features of the game in my opinion)
For a game you haven't played, its a good laugh granted you like super heroes, but after 3 years of play it can get kinda boring... untill it goes free this autumn =P
So yeah, that's my experience with the game, make of it what you will. =)