IE7 is still roaming around out there. On my own sites, visitor percentages for IE7 are now down into the mid-single digits, however, and dropping fast. IE9 is already accounting for more visitors than IE7. IE8 runs just fine on WinXP, so there aren't many good excuses for sticking with IE7.
I have the luxury of not doing stuff for commercial sites, so I take a "close enough" approach to IE7. In other words, as long as the page looks and behaves pretty much the same, I'm not going to bother trying to track down small differences in spacing and positioning.
IE6 is a tougher one to deal with, of course. There are still huge numbers of IE6 users in China, for example. Dealing with the coding changes needed to accommodate it can be miserable. But I figure if people like Google Apps and Facebook can throw the IE6 users to the wolves, so can I.