help me choose better phone, please

THIS IS MY CURRENT PHONE

nokia 7900 Prism 

 

Exchange to :

i Phone?

  
or

  
Xperia Pureness

by Sony Ericcson?

which one's better? i love the design Pureness' design, but what i have to consider is, that pureness doesn't have any camera, colors or internet because the screen is see through, but that's a good thing.  However, i still need functional cellphone. Well, i don't know yet

Help me