That's where we differ. I just can't believe that someone who is a good, honest person will go to hell because he hasn't "accepted" Jesus Christ. You can believe whatever you want, that's fine with me. But your putdown of Islam (and many other religions, now that things are in perspective) leaves your biases in plain view, and I don't like how you act like you're refusing to accept followers of other religions on the same level as yourself. I might be wrong, but that's the impression I'm getting, and it offends me.
C.S. Lewis seems to believe that Hell may very well be a place of bitterness and inwardness. I personally do not think it's really a lake of fire. I do not think being in Hell is like that. I think those in Hell are bitter and resentful and only think of themselves, so that they would not choose to leave. I see Hell as chosen.
There's another issue here: can someone be good and honest without following Jesus? I wouldn't be so sure. Maybe by our standards...but obviously I think there's more to it than that.
Anyway, regarding your last few sentences: from a secular standpoint, yes, he's basically on the same level...but certainly you cannot fault him for believing himself to be correct over the others. That's why he believes what he believes; because he thinks it superior.