Last night Yahoo! Maps beta released 1-meter/pixel resolution color satellite photos for the entire continental US. This is significant because it is more consistent data instead of the patchwork of varying color, black and white, varying resolution imagery we are used to in other mapping applications like Google Maps/Earth, and Windows Live Local. Yahoo! now has the best medium resolution dataset for the entire continental US.
I've been using Yahoo! Maps beta for a while now. I'm a big fan for a host of reasons and now with these sat photos there's no reason to use anything else.
You might also want to check out MSN Live - http://local.live.com/
I'm also a big fan of that option, as it combines local news/data with excellent mapping API.