IMO Tony you should get the most expensive handset you can and flog it!! I've been through loads recently and you know which 1 i'm using now bud!!
Nokia N96 you can get £400+ for on ebay.
Nokia N95 8Gb are still fetching £200+.
If you still want to get a new phone then make sure you get the new model iphone. But remember it will be gettin taken out on the beach with you getting wet and fishy fingers all over it
You can't go wrong with the phone you have bud. Maybe just buy a new 1 if it's starting to look tatty.
As with most of the new phones the iphone is very overrated and not very practical for the beach!!!!