It depends really

Usually if an end user has a true static IP address then to comply with Best Practices and satisfy most receving MTA's forward and reverse DNS entries should be configured , the SPF record is just another bolt on to satisfy the receiving MTA's .

For most case's the IP's wont even be blacklisted but flagged within a DUHL / PBL list and marked as dynamic , and most receiving MTA's dont expect to get email from a dynamic IP as thats the first alarm bell to it being spam , users of dynamic IP's should utilise the SMTP server of their ISP. If the Listing is wrong then most of the ISP's can request the list is updated to reflect the IP's new usage and mark it as static .

With Broadband speeds getting as fast as they are , and the fact most ISP's now offer true static IP's then I think most of the larger companies will start taking them up instead of paying thousands for a Dedicated connection , the only thing they may loose is someService support in the event of an outage but even those dont crop up that often anymore and are usually fixed in 24 hours .