I figure your head and it's contents are worth whatever you're willing to throw at them. What's your head worth to you? I worked years ago with people who had suffered traumatic brain injuries. Not a place you want to be if you can help it.
Another aspect is fit. Different people have different shaped heads and different brands fit differently. I just plain don't fit into a Shoei. Arai, on the other hand, fit me better, but only once I customize the padding. HJCs used to fit me pretty good, but not so much any more...
I have an Arai XD3. It used to fog up way too easy, but it's much improved since I got a pinlock antifog shield and I love it. I also have an HJC which is a lot cheaper, but good for my commute
Try on a variety and get the best you can afford.