i have good sunlight but no real windowsill. however ouside my window theres almost a platform where the roof meets the gutter so i might be able to put something there provided its not to much of an eye sore + my parents will think its odd im planting vegies on our roof.
cactuses sound like a good idea, low maintanance and bring alot of life to the room one of my friends suggested a particular species (cant remember which one) so ill have a look into that a tell you how it goes.