I guess it depends if the personalised alerts is a deal breaker for you or not. It wouldn 't be for me, I wouldn't be without my iphone. I soon got over not having personalised tones after about a week mainly due to the huge number of advantages the iphone would bring you, its brilliant, I can't rate them highly enough. Like Rach said no crashing with the iphone like there is with the blackberry. My only critiscm of the iphone is the battery life, but I have a mains charger in my bedroom and at work so i soon got over that as well.
There are just so many apps available. I have orange wednesday, my bank statements and balance, phone text/mins balance, games, sky news, bbc news, facebook, ebay, iwatcher, whatsapp (a MUST have - instant messaging app so you can chat to other iphone users for free), pedometer, walk/run programme, sit ups programme, met office - thats just a few apps I have on there. The internet is pretty decent on there too.
If you do get one think about getting a screen protector and skin to keep it safe!