The original storm was supposed to be the worst phone ever – the only person I know with one absolutely hates theirs. Personally I'd get something with a proper web browser that isn't a bit rubbish (which probably means either Apple or something Android) unless you're a complete email fiend.
With your N96, it is worth running nokia software updater on it if you haven't already – as it is much much more stable with the latest software.
Also, if you do get a new phone, don't forget to ebay your N96. If you have the bits that come with it, they go for about £200 nowadays (if you have the box, you might get slightly more, same if it is unlocked).
Joe