I understand that the minimum disk allocation block is 4kb, but in Finder I don't really care about that. I'd much rather be able to see which of 12 similar text files/images is largest, expecially because I do web work and it's very useful to see the actual size of your files without having to 'get info' on all of them.
There's no simple option I can see, but if there's a terminal command or file somewhere I can edit, I'd love to be able to.
I'm using Snow Leopard 10.6.5, btw. :)