You can repair the phone and it is more economic to repair than buying a new one.
Google can find you places to buy replacement screen or on eBay. It might be worth getting a digitiser also if the touch sensitivity does not work anymore. Videos can be found on youtube to show you the replacement procedure, it is not particularly difficult.
YouTube - Blackberry Storm 2 9550 Take Apart LCD Touch Screen Digitizer
If you wish to buy a new phone, the 'best' blackberry is the one that suits you and your needs. Use the compare facility on blackberry.com to get a rough overview of devices available or speak to your carrier, they will be more than happy to assist you.