I'll mostly echo Jerick here in that I like RP heavy games but can understand why some would not. From what I've seen most games that have much concept of actual RPing have alternate servers for players who prefer RPing, or at least guilds who do so.
Everquest for example had the Firiona Vie server, which was their roleplaying preferred server. Very few items were no drop, allowing even many raid items to be traded or sold to anyone you wanted to. The languages used by each species were more rigidly enforced in that, if I recall correctly, every species had a different language and you had to learn new languages to interact with players and NPCs of another species. "Evil" and "good" aligned players couldn't mix in groups, unless a "neutral" aligned player was the group leader.
It's a pretty cool concept, but the server suffered a lot as players left Everquest in general, and is now mostly a ghost town from what I hear.
On the normal servers there are often guilds that do this. They'll place restrictions on player conduct to encourage roleplaying, such as only accepting evil or good aligned members. I think these are mostly nonexistant now.
I never really got into the RPing in Everquest all that much, for one reason or another. I think it's because I mostly solo and thus had little reason to, but I did try to keep up a minimal level of it. I played as a paladin, and went out of my way to avoid attacking friendly or neutral NPCs and fought undead where I could find them even before I had any spells to help make them more worthwhile targets.
I'd actually really like to see an MMO that focused on the RP aspects of playing more than just grinding and gameplay mechanics.