RuneScape isn't the best online game, but weakly updates make it better.
The quests usually aren't very fun, and almost nothing about the game is epic. The most epic quest I did was Underground Pass. Man, that quest was awesome. There are a lot of places to explore, like Falador, Seers, Varrock, Lumbridge, Plague City, and a lot more, unfortunately, you've gotta be a member to go to most of these places.
There WAS Player Killing (Or PKing), but the newest update got rid of that, and that's just awful. There are tons of problems involving trading and stuff, but it's usually alright. You can have 200 friends on your list, and you can have a clan. There are some good ideas in RuneScape, however none of them are executed very well.
Pros: Some fun quests. A lot to explore. You can customize your character. Some good ideas here and there. Forums. Weakly updates.
Cons: Weakly updates. Bad graphics, horrible music and awful sound effects. Player Killing is gone, and now the wilderness is pointless. Making money is hell. Fighting is as simple and boring as clicking an enemy and hoping that you don't die. Not very epic. "Loading... Please Wait"
You should give RuneScape a try, and if you like it, give members a try. You free trial is unlimited, so go ahead. I'd recommend it. :)