You're asking subjective questions that are a matter of opinion. My idea of user friendly is probably very different from yours, and ours is probably very different from the next person we would ask, and so on. User friendly is a highly abstract phrase that has no clear meaning, which is intentional on the part of Apple and Microsoft's respective marketing departments.
Now, as Bob said, IE is unsafe to use for pretty much any length of time. It's still far too easy for malware to slip in, and given Microsoft's history on security, I very much doubt that IE7 will be any different from IE6 in terms of the need for regular patching.
Your non-IE choices on Windows are Seamonkey, Mozilla Firefox, and Opera. Technically speaking, Seamonkey and Firefox are the same core browser, Seamonkey just carries on the legacy of the old Mozilla suite, which included an email program, web page composer, and a few other tools. All three are free, so pick whichever one you like best, and stop using IE for anything but downloading Windows Updates patches.