it depends on what you want out of a phone, if you want to make calls, play games, takes photo,s facebook and all that stuff then....throw a stone. how much do you want to spend?
16 quid a month gets you an s2 which a year ago was an awesome phone (and still is)
25 quid a month gets you an s3 with enough data/text/mins you will need
30 quid a month gets you an iphone 4s with probably enough of what you need
46 quid gets you an iphone 5 with well nothing really more than any of the above other than the 'kudos' of being like 20 million other people who have just bought one because "its the best iphone yet" (untill june next year for the 5s
i dont think you would be disapointed with any of them although you may question why your paying 46 quid a month for nothing extra.
i got a galaxy note on a 21 quid a month contract. same screen as the s3 but bigger, same processor as the s2 but faster. same memory as the iphone but expandable. and i dont have to go through itunes telling me the film i just downloaded cant be played. (yes it can its just apple wont allow it)
good luck with whatever you buy, it will be a moot point in 6 months time anyway
1998 GT lts.1990 fisher montare/procaliber tribute.
1984 raleigh record sprint and the full set of Pacific Blue on dvd.