Sluggish cursor movement in emacs in Lion Terminal?
Are you using a translucent terminal window appearance? Terminal now supports window background blur in addition to translucency, and existing settings profiles default to 20% blur (except Pro, which uses 0%). If you have a large terminal window and/or slower hardware, you may notice some slow down when moving around in emacs (compared to vim, emacs is noticeably inefficient about updating the display when moving the cursor around and redraws a lot, which requires redrawing the background).

Try selecting a different profile or edit the profile to disable blur:


  Terminal > Preferences > Settings > [profile] > Window > Background > Color