OK - this is all the wife's fault 
She has a contract with O2.
She pays very little a month - because she doesn't need loads of minutes/texts.
She isn't due a handset upgrade for a while.
She has decided that she wants a "touch" phone - I expect more for the novalty than anything else.
So with Christmas coming I thought I'd see what I could get her.
What "touch" phones are out there which I could buy contract free (maybe somebody selling an upgrade on EBay kind of thing)?
I really don't know what is out there - so what good "touch" phones are out there right now (including old models)?
What should be avoided at all costs?

She has a contract with O2.
She pays very little a month - because she doesn't need loads of minutes/texts.
She isn't due a handset upgrade for a while.
She has decided that she wants a "touch" phone - I expect more for the novalty than anything else.
So with Christmas coming I thought I'd see what I could get her.
What "touch" phones are out there which I could buy contract free (maybe somebody selling an upgrade on EBay kind of thing)?
I really don't know what is out there - so what good "touch" phones are out there right now (including old models)?
What should be avoided at all costs?