Depending on your house, the home antennas may not do much good. Per the chart on sirius.com, I need to face the antenna pretty much straight north. However, all my windows face east, and the eaves are pretty deep. So here's what I did:
1. Buy a car antenna.
2. Stick it to a metal lid from a popcorn tin.
3. Place the antenna outside where it has a clear view of the sky, and run the cord through the window to the home dock.
4. Enjoy the incredible signal strength.
Of course, there are "cleaner" ways to do this, but this was a great solution for my ground-floor stereo-next-to-window situation.