Hey, you could try out Eve Online. It's not for everyone, but a fantastic and engrossing game for those that have the intelligence and patience for it. I know of many MMORPG fans who've tried it out and never looked back.

I think your comp should be able to run it ok.

If you want to try it out this is a link to an extended 21 Day Free Trial.

https://secure.eveonline.com/trial/?invc=85a15492-dad8-4bd2-9818-33ce078cfaf3&action=buddy