It's going to depend greatly on your settings. Mine will actually dip into the teens when I'm on a flyer flying over Ashenvale, but it will regularly hit 60 as well in more confined areas - I run at 1680x1050 6xAAA/16xHQAF vsync on. Prior to the weather patch, I never saw dips as low as that, but I like the weather effects so I keep them enabled and on high. Generally, instances are closed spaces, so I imagine that the FPS will stay high and will actually be more cpu than gpu dependent. I don't have any shots of the fps in WoW, but the rig in your sig with an X1900XTX would be awesome for WoW.