I can't really recommend WoW, had you asked a few years ago I would ahve, but there's a reason I stopped playing after 5 years. RIFT is a very good game, but it is a WoW clone, make no mistake. That is in no way bad but the fact that it's so similar means I couldn't enjoy it for long, why quit one game and go to one that's almost exactly the same?
Right now I'm playing Champions Online. It's free to play, but I wouldn't recommend that considering how much better the game is when you pay for it, well worth the money. Keep in mind though that it's not an end-game focused game. It relies heavily on players willing to make alts and explore different powersets and concept for their heroes, the power system itself is (If you pay. Free players need to pick a class, paying players do not, they can pick and choose individual powers and essentially do anything in terms of character builds) very broad and offers a ton of possibilites to experiment or find interesting synergies or concepts. It also has a relatively big focus on roleplaying, with several RP guilds and a nightclub that's pretty much the go to spot for roleplaying, as well as other locations around the gameworld.
I'd recommend the game if you like superheroes, great character customisation and a fun gameworld. If you're more focused on end game such as WoW's raiding then it may not be for you.
Don't get me wrong on WoW by the way, I grew tired of it because I played it for so long and ebcause Blizzards focus shifted towards a different demographic that I'm not part of. The game just isn't for me anymore.
I second Minecraft. Strange how a game can make you want to dig deeper just to dig deeper to dig deeper to... You'll know what I mean.
I don't like digging. On our server we just spawn the stuff we need then build awesome things. It's satisfying when you get the materials themselves sure, but for me the real fun is coming up with an idea and then seeing it done. I'd rather spend my time having fun rather than doing something I don't like as a chore first.
Once we get more players though, they'll have to dig, only two of us will keep our admin powers