RuneScape 2007 Servers
If you're one of those that played and loved RuneScape, but isn't a big fan of the (d)evolution in the recent years, you might be interested in this:

That's right; Jagex has launched servers with the 2007 patch in effect. They're pretty stable and well populated. You need a members subscription to play on them, though.
I tried playing RS again after stopping since I was out of middle school. It was cool at the time, but pales in comparison to modern MMOs.