first of all, none of you should be using the iPhone as your primary source of music and entertainment, if you are, you're using it wrong. The iPhone in no way replaces all your other media devices. Yes it's fun to have everything in one place, but that doesn't mean you should disregard your iPods and DVD players, not yet at least.
Secondly, 8 gig is PLENTY right now, I have a bunch of things on there, most of them to show off as demos and I'm nowhere near filling it. Thinking about it, I find it funny that whatever capacity they come out with, people feel compelled to completely fill it, why is that? You don't get a prize for that. OOOOOHHH they came out with an 80gig iPod, I must scramble to find 80gig of media so I can fill it immediately. silly.