sohtnax,
I think you need to first digest what it means to be assigned an IP address range from an ISP. When the ISP grants you a new public IP range, they are effectively "routing" this range to your internet router. It does not mean you have to load all the IPs into your router like its some sort of CD-staker.
Decide what you want to do with IP address. You may want to assign public IPs to your web or application servers. If so, then on your router, simply create the access-list/route statement to allow traffic access the host with the new public IP. You may not use all IPs asssigned to you, so just add access-list/route statements for the public IPs you use.
The ISP still offically own the IP range, they simply administer where to route IP range. When you change ISP, they will revoke the IPs from you, assign it to a new customer and start routing traffic for that IP range to the new customer's internet router.
JimmyZ