I have many Windows 7 machines running at work and none of them manifests a problem with Explorer.
A classic cause of Explorer crashes is a buggy Explorer extension. Explorer extensions change the display of folders or items within folders. If these extensions are buggy, they can crash Explorer. Unfortunately, many software products install them, and some computers with pre-installed, "home-grown" versions of Windows may have such extensions in place, too.
Normally, such gadgets allow items in certain folders to be displayed in non-standard ways. For example, a folder containing pictures in a proprietary format could display thumbnails for those pictures with an extension. But since they live right inside Explorer, a program that is sorta-kinda part of the OS, they can crash this essential program if they fail. (This is one reason why I was never in favor of the Windows 95 Explorer being cloned into NT and its successors, but I guess it's too late now.)
Anyway, if you are getting Explorer crashes, you might try to find out if you have anything in the system that might try to display the contents of certain folders in a different way, or any other extensions to Explorer.