Thanks all, regarding thinner/lighter/better looking etc, I bought my iPhone 4 on day one, and straight away stuck it into a 69p
jelly case which made it look bloody awful, and a bit bigger anyway - I imagine I'd do the exact same with the 5 because it's so practical.
A bigger screen would be nice, but I'm disappointed they've basically just made it a bit taller. Seems like a bit of a cop out to me - can't be bothered to tweak the OS beyond just adding another row.
I'm seriously considering just being behind the curve, and getting a yearly update - always one phone model behind. Not sure how much I'd save that way over the buying new and keeping for two years that I do now.