In relation to Xbox Live? There are no advantages or disadvantages. In relation to the broader internet? Really, the only reason why you would need/want a static IP is if you were going to host content, even then you only really need a static IP is if you
needed some kind of SSL certificate.
If you wanted to pursue a static IP, you would need to talk to your ISP sales department to discuss the relevant fees etc.
Did this solve your problem?
Sorry this didn't help.
Great! Thanks for marking this as the answer.
How satisfied are you with this reply?
Thanks for your feedback, it helps us improve the site.