[Update, Dec 2015: My landlord has informed me that this sort of window-wire-dangling is prohibited by the terms of my lease. It was freaking out some of the neighbors, who thought it was a camera that I was using to spy on them. I'm working on an alternate solution that will keep me in compliance with the lease while still allowing me to operate from my home.]
Living on the eighth floor of an apartment building in downtown San Francisco isn't an ideal environment for an amateur radio station. I can't put up any permanent antennas on the building, and we have very little space for my equipment inside.
Here's my current solution to that problem.
The antenna is a Chameleon Hybrid Mini 5:1 unun attached to sixty feet of wire, dangling above Stevenson St. The antenna is attached to a long extension pole, which I carefully extend about ten feet out my eighth floor window. On the opposite end of the unun is a homemade set of four counterpoise wires. The two long counterpoise wires run inside the apartment and under the carpet, while the two shorter wires hang down outside the window. I can run all bands, 160 through 6 meters, but I do have to use the internal ATU in my FT-450D.
This setup takes about ten minutes to deploy or take down, which is great. I haven't done any antenna pattern modeling, but if I did, I suspect I would find that the antenna's close proximity to the building degrades its performance. In addition, downtown SF is an extremely noise-rich environment, both to the human ear and to my radio.
I think I get better results by going on the roof with a portable vertical and my KX3. I may eventually abandon operating from inside my apartment at all, in favor of weekend portable operation from the roof or local parks. The main advantage here is that I can have a relatively normal operating position, sitting at my desk, with a 100 watt radio and a computer.