We've currently got Ctrl+Drag (or Cmd+Drag on OS X) for panning around the workspace, and the mouse wheel up/down is mapped to zooming in/out. (Probably need to better document these somewhere!) Compatibility with other keyboard/mouse conventions is something I will pass on to the UI team.

Agree about "amazingly useful ... lightning fast" to switch between modes -- we just added a keyboard shortcut for re-running the last simulation, just so we could eliminate the burden of explicit mode switching between schematic capture and simulation.