Ok, I have a thought if you're thinking about designing a massively multiplayer on line role playing game. Play World of Warcraft. About 25 hours of it, at least.
I have the honour of being in the beta for an MMORPG. I have not read the EULA or NDA, but I will go out on a limb and assume I can't tell you what it is or any details about it. It doesn't suck, in fact parts of it are well done. But a lot of it looks like somebody trying to re-invent the wheel.
Now, it is a beta so I am willing to let a fair bit slide. However, the bits I'm talking about are the core game, and not all that likely to change. It needs work.