I was rather motivated last week, so I decided to switch the Snes9X display code from DirectDraw to Direct3D9.
The advantages are an optional bi-linear filter and no problems with Aero on Vista.
One disadvantage: I´ve been unable to get the menu to work in fullscreen without flickering, so I´ve disabled that for now (ESC now exits fullscreen).

OpenGL should still work, but it is still hidden from the GUI.

Small update 26.11.2008:
-the display modes list became corrupted when switching between DirectDraw and Direct3D

Changes/fixes:
-Direct3D output (optional)
-fullscreen mode respects refresh rate setting (d3d only)
-updated graphics option dialog
-"Text in Image" now works correctly in 32 bit
-turbo-mode toggle works with gamepads
-"local vid-mem" and "test mode" in display settings have been disabled
-ESC in fullscreen now exits fullscreen
-new filter: blargg´s ntsc filter (three presets)