Google Maps + Terraserver
If you live in or around a big city, then Google Maps provides you with high-resolution satellite imagery of your area. But in more rural areas, the available satellite imagery is much lower resolution.
Terraserver on the other hand has always seemed to have high-res photos of nearly everywhere in the US. They may be a little older and in black & white, but it’s better than having no high-res imagery at all. But the problem is that after being introduced to the joy of the Google Maps interface, Terraserver’s boring old interface is such a pain to use.
Enter mapper.acme.com. This site combines Google Maps with the imagery database from Terraserver. Just use the "DOQ" link in the upper right-hand corner.