Being unable to make up our minds, we need some help. Upgrading 2 phones for my teenage girls with O2 (getting a good deal). Daughter no 1 is certain to go for the Sony Ericsson K750i. Daughter no2, however, is as decisive as I am and cannot choose between the Motorola V3, the Samsung E530 or the Samsung Z500. Researching the web has just confused me even more. Help please.