Being good-looking can definitely open doors and give you oppertunties that others don't have. BUT, your looks will not SUSTAIN you through most of those oppertunites if that's all you've got. Obviously, if the oppertunity is something specifically to do with your looks (model, Hugh Hefner's "girlfriends", etc.), then maybe, but for most other things, you have to have more than just looks.
It's one of those "life isn't fair" issues that we all love to hate.