I know no one knows for sure, but how much space is the HD video going to take up? I currently have a 16GB iPhone 3GS and will be upgrading to the iPhone 4. My 3GS has 1.7 GB free memory and I have very little music, etc. on it. Mostly apps and a couple movies. I am thinking of dropping the extra $100 for the 32GB. Do you think it is a worthy upgrade for the money? Thanks!