This has been a really interesting topic to me. Thanks to Slaninar for starting it, and thanks for a lot of the comments in it.

I just want to add a couple of things. If you have a heavier bike, the ideal tire pressure will increase a bit.

And I was on an upper class bike site not long ago. They mentioned that going for the super competitive advantage of an extremely light bike, means you will get one that is not going to last as long. I thought it was decent of them to mention that.